Comparison of clinicopathological characteristics and survival outcomes between gallbladder mucinous adenocarcinoma and gallbladder adenocarcinoma:A propensity score-matched study

BACKGROUND Gallbladder mucinous adenocarcinoma(GBMAC)is a rare subtype of gallbladder adenocarcinoma(GBAC),with limited knowledge of its survival outcomes from small case series and single-center retrospective analysis.AIM To compare the clinicopathological characteristics of GBMAC with typical GBAC and its prognostic factors to gain insights into this field.METHODS This study was conducted using data from the Surveillance,Epidemiology,and End Results database,including cases of GBMAC and typical GBAC diagnosed from 2010 to 2017.The Pearson chi-square test or Fisher exact test was used to examine the differences in clinicopathological features between these two cohorts.In addition,propensity score matching(PSM)analysis was performed to balance the selection biases.Univariate and multivariate Cox hazards regression analyses were performed to determine independent prognostic factors for cancer-speci
c survival(CSS)and overall survival(OS).The Kaplan–Meier curves and log-rank tests were used to assess the OS and CSS of GBMAC and typical GBAC patients.RESULTS The clinicopathological and demographic characteristics of GBMAC were different from typical GBAC.They included a larger proportion of patients with unmarried status,advanced American Joint Committee on Cancer(AJCC)stage,higher T stage,higher N1 stage rate and lower N0 and N2 stage rates(P<0.05).Multivariate analyses demonstrated that surgery[OS:Hazard ratio(HR)=2.27,P=0.0037;CSS:HR=2.05,P=0.0151],chemotherapy(OS:HR=6.41,P<0.001;CSS:HR=5.24,P<0.001)and advanced AJCC stage(OS:Stage IV:HR=28.99,P=0.0046;CSS:Stage III:HR=12.31,P=0.015;stage IV:HR=32.69,P=0.0015)were independent prognostic indicators for OS and CSS of GBMAC patients.Furthermore,after PSM analysis,there was no significant difference between GBMAC and matched typical GBAC patients regarding OS(P=0.82)and CSS(P=0.69).CONCLUSION The biological behaviors of GBMAC are aggressive and significantly different from that of typical GBAC.However,they show similar survival prognoses.Surgery,chemotherapy,and lower AJCC stage were associated with better survival outcomes.Further research is needed in the future to verify these results.

Waist subcutaneous soft tissue metastasis of rectal mucinous adenocarcinoma: A case report

BACKGROUND Rectal mucinous adenocarcinoma(MAC)is a rare pathological type of rectal can-cer with unique pathological features and a poor prognosis.It is difficult to diag-nose and treat early because of the lack of specific manifestations in some aspects of the disease.The common metastatic organs of rectal cancer are the liver and lung;however,rectal carcinoma with metastasis to subcutaneous soft tissue is a rare finding.CASE SUMMARY In this report,the clinical data,diagnosis and treatment process,and postope-rative pathological features of a patient with left waist subcutaneous soft tissue masses were retrospectively analyzed.The patient underwent surgical treatment after admission and recovered well after surgery.The final pathological diagnosis was rectal MAC with left waist subcutaneous soft tissue metastasis.CONCLUSION Subcutaneous soft tissue metastasis of rectal MAC is rare,and it can suggest that the tumor is disseminated,and it can appear even earlier than the primary ma-lignant tumor,which is occult and leads to a missed diagnosis and misdiagnosis clinically.When a subcutaneous soft tissue mass of unknown origin appears in a patient with rectal cancer,a ma-lignant tumor should be considered.

Mucinous adenocarcinoma:A unique clinicopathological subtype in colorectal cancer

Mucinous adenocarcinoma(MAC)is a unique clinicopathological subtype of colorectal cancer,which is characterized by extracellular mucinous components that comprise at least 50%of the tumor tissue.The clinical characteristics,molecular features,response to chemo-/radiotherapy,and prognosis of MAC are different from that of non-MAC(NMAC).MAC is more common in the proximal colon,with larger volume,higher T-stage,a higher proportion of positive lymph nodes,poorer tumor differentiation,and a higher proportion of peritoneal implants compared to NMAC.Although biopsy is the main diagnostic method for MAC,magnetic resonance imaging is superior in accuracy,especially for rectal carcinoma.The aberrant expression of mucins,including MUC1,MUC2 and MUC5AC,is a notable feature of MAC,which may be related to tumor invasion,metastasis,inhibition of apoptosis,and chemo-/radiotherapy resistance.The genetic origin of MAC is mainly related to BRAF mutation,microsatellite instability,and the CpG island methylator phenotype pathway.In addition,the poor prognosis of rectal MAC has been confirmed by various studies,and that of colonic MAC is still controversial.In this review,we summarize the epidemiology,clinicopathological characteristics,molecular features,methods of diagnosis,and treatments of MAC in order to provide references for further fundamental and clinical research.

Mucin phenotype of gastric cancer and clinicopathology of gastric-type differentiated adenocarcinoma

Differentiated adenocarcinoma of the stomach is classified into gastric or intestinal phenotypes based on mucus expression. Recent advances in mucin histochemistry and immunohistochemistry have highlighted the importance of such a distinction, and it is important clinically to distinguish between gastricand intestinal-type differentiated adenocarcinoma. However, a clinical and pathological diagnosis of this type is often difficult in early gastric cancer because of histological similarities between a hyperplastic epithelium and lowgrade atypia. Furthermore, determining tumor margins is often difficult, even with extensive preoperative examination. It is therefore critical to consider these diagnostic difficulties and different biological behaviors with high malignant potential when treating patients with gastric-type differentiated adenocarcinoma.

Dissimilar survival and clinicopathological characteristics of mucinous adenocarcinoma located in pancreatic head and body/tail

BACKGROUND Growing evidence shows that pancreatic tumors in different anatomical locations have different characteristics,which have a significant impact on prognosis.However,no study has reported the differences between pancreatic mucinous adenocarcinoma(PMAC)in the head vs the body/tail of the pancreas.AIM To investigate the differences in survival and clinicopathological characteristics between PMAC in the head and body/tail of pancreas.METHODS A total of 2058 PMAC patients from the Surveillance,Epidemiology,and End Results database diagnosed between 1992 and 2017 were retrospectively reviewed.We divided the patients who met the inclusion criteria into pancreatic head group(PHG)and pancreatic body/tail group(PBTG).The relationship between two groups and risk of invasive factors was identified using logistic regression analysis.Kaplan-Meier analysis and Cox regression analysis were conducted to compare the overall survival(OS)and cancer-specific survival(CSS)of two patient groups.RESULTS In total,271 PMAC patients were included in the study.The 1-year,3-year,and 5-year OS rates of these patients were 51.6%,23.5%,and 13.6%,respectively.The 1-year,3-year,and 5-year CSS rates were 53.2%,26.2%,and 17.4%,respectively.The median OS of PHG patients was longer than that of PBTG patients(18 vs 7.5 mo,P<0.001).Compared to PHG patients,PBTG patients had a greater risk of metastases[odds ratio(OR)=2.747,95%confidence interval(CI):1.628-4.636,P<0.001]and higher staging(OR=3.204,95%CI:1.895-5.415,P<0.001).Survival analysis revealed that age<65 years,male sex,low grade(G1-G2),low stage,systemic therapy,and PMAC located at the pancreatic head led to longer OS and CSS(all P<0.05).The location of PMAC was an independent prognostic factor for CSS[hazard ratio(HR)=0.7,95%CI:0.52-0.94,P=0.017].Further analysis demonstrated that OS and CSS of PHG were significantly better than PBTG in advanced stage(stage III-IV).CONCLUSION Compared to the pancreatic body/tail,PMAC located in the pancreatic head has better survival and favorable clinicopathological characteristics.

Clinical pathological characteristics of“crawling-type”gastric adenocarcinoma cancer:A case report

BACKGROUND Gastric cancer(GC)is a significant health problem worldwide,and early detection and accurate diagnosis are crucial for improving patient outcomes.Crawling-type gastric adenocarcinoma is a rare subtype of GC that has unique histopathological and clinical characteristics,and its diagnosis and management can be challenging.This pathological type of GC is also rare.CASE SUMMARY Here,we report the case of a patient who underwent ordinary endoscopy,na-rrow-band imaging,and endoscopic ultrasonography intending to determine the extent of tumor invasion and upper abdominal enhanced computed tomography and whether there was tumor metastasis.Then,endoscopic submucosal dissection was performed.After pathological and immunohistochemical examination,the pathological diagnosis was crawling-type gastric adenocarcinoma.This is a very rare and special pathological type of tumor.This case highlights the importance of using advanced endoscopic techniques and pathological examination in diagnosing and managing gastric crawling-type adenocarcinoma.Moreover,the findings underscore the need for continued research and clinical experience in this rare subtype of GC to improve patient outcomes.CONCLUSION The“crawling-type”GC is a rare and specific tumor pathology.It is difficult to identify and diagnose gliomas via endoscopy.The tumor is ill-defined,with a flat appearance and indistinct borders due to the lack of contrast against the background mucosa.Pathology revealed that the tumor cells were hand-like,so the patient has diagnosed with“crawling-type”gastric adenocarcinoma.

Limited, local, extracolonic spread of mucinous appendiceal adenocarcinoma after perforation with formation of a malignant appendix-to-sigmoid fistula: Case report and literature review

A 68-year-old man presented with progressive right lower quadrant abdominal pain and tenderness without rebound tenderness, and with constipation during the prior 9 mo. Abdomino-pelvic computed tomography and magnetic resonance imaging demonstrated a dilated appendix forming a fistula to the sigmoid colon. Open laparotomy revealed a bulky abdominal tumor involving appendix, cecum, and sigmoid, and extending up to adjacent viscera, without ascites or peritoneal implants. The abdominal mass was removed en bloc, including resection of sigmoid colon, cecum(with preservation of ileocecal valve), appendix, right vas deferens, testicular vessels, and minimal amounts of anterior abdominal wall; and shaving off of small parts of the walls of the urinary bladder and small bowel. Gross and microscopic pathologic examination revealed an appendix-to-sigmoid malignant fistula secondary to perforation of mucinous adenocarcinoma of the appendix with minimal local spread(stage T4). However, the surgical margins were clear, all 13 resected lymph nodes were cancer-free, and pseudomyxoma peritonei or peritoneal implants were not present. The patient did well during 1 year of follow-up with no clinical or radiologic evidence of local recurrence, metastases, or pseudomyxoma peritonei despite presenting with extensive stage T4 cancer that was debulked without administering chemotherapy, and despite presenting with malignant appendiceal perforation. This case illustrates the non-aggressive biologic behavior of this low-grade malignancy. The fistula may have prevented free spillage of cancerous cells and consequent distant metastases by containing the appendiceal contents largely within the colon.

Relationship between clinicopathological features and mucin phenotypes of advanced gastric adenocarcinoma

AIM: To investigate a relationship between the clinicopathological features and mucin phenotypes in advanced gastric adenocarcinoma (AGA). METHODS: Immunohistochemical staining was performed to determine the mucin phenotypes in 38 patients with differentiated adenocarcinomas (DACs), 9 with signet-ring cell carcinomas (SIGs), and 48 with other diffuse-type adenocarcinomas (non-SIGs) of AGA. The mucin phenotypes were classified into 4 types: gastric (G), gastrointestinal (GI), intestinal, and unclassified. RESULTS: The G-related mucin phenotypes were highly expressed in all the histological subtypes of AGA. The expression of the GI phenotype in SIG patients was lower than that in DAC patients (P = 0.02), and this phenotype was observed in 56% of the non-SIG patients in the intramucosal layer. Among non-SIG cases, the expression of the GI phenotype was significantly higherin patients with extended adenocarcinomas and those with positive rates of lymph node metastasis. There was no difference between the expressions of the G and other GI phenotypes factors. Among DAC and non-SIG patients, there were no differences between the survival rates of the corresponding patient groups. CONCLUSION: The GI phenotype might possess more invasive characteristics than the G phenotype in nonSIG. Neither of the phenotypes indicated a poor prognosis of DAC and non-SIG.

Primary Mucinous Adenocarcinoma of the Thymus: A Case Report and Literature Review

THYMIC carcinoma is a rare malignant tumor, but the most common malignant tumor of the ante-rior mediastinum. According to the latest World Health Organization （WHO） classification, primary thymic carcinoma has a variety of histological types, mainly including squamous cell, basaloid, mucoepidermoid,lymphoepithelioma-like, sarcomatoid, clear cell and neuro-endocrine carcinomas, and papillary adenocarcinoma.1-4 Thymic mucinous adenocarcinoma was discovered in re-cent years, and only 10 cases were reported. In this paper, we described a case of thymic mucinous adenocarcinoma, the histopathological findings and immunohistochemical results.

SIGNET-RING MUCINOUS ADENOCARCINOMA OF THE PANCREAS

An 88-year-old man presented symptoms and signs of ascending cholangitis and died 20 days after the onset of illness. Postmortem examination revealed a mucinous tumor arising from the head of the pancreas, encasing the common bile duct and invading the liver with multiple hepatic metastasis. The tumor showed a unique and uniform histological apperarance, consisting of signet-ring neoplastic cells floating in mucin pools. The rapid clinical course and widespread hepatic metastasis of this patient suggest that this pure, signet-ring variant of mucinous adenocarcinoma of the pancreas might have a poorer prognosis.

Mucinous phenotype and CD10 expression of primary adenocarcinoma of the small intestine

AIM:To clarify the correlation with phenotypic expression,clinicopathological features,genetic alteration and microsatellite-instability status in small intestinal adenocarcinoma(SIA).METHODS:The cases of 47 patients diagnosed with primary SIAs that were surgically resected at our institution in 1975-2005 were studied.We reviewed clinicopathological findings(age,gender,tumor size,gross appearance,histological morphologic type,invasion depth,lymphatic permeation,venous invasion,and lymph node metastasis),and the immunohistochemical expression of MUC5 AC,MUC6,MUC2,CD10,and mismatch-repair(MMR) proteins(MLH1 and MSH2).We analyzed KRAS and BRAF gene mutations,and the microsatellite instability(MSI) status.The immunohistochemical staining of CD10,MUC2,MUC5 AC and MUC6 was considered positive when distinct staining in > 5% of the adenocarcinoma cells was recorded.To evaluate of MMR protein expression,we used adjacent normal tissue including lymphoid follicles,inflammatory cells,and stromal cells as an internal positive control.Sections without nuclear staining in the tumor cells were considered to have lost the expression of the respective MMR protein.RESULTS:There were 29 males and 18 females patients(mean age 59.9 years,range:23-87 years).Tumors were located in the duodenum in 14 cases(30%),the jejunum in 21 cases(45%),and the ileumin 12 cases(25%).A phenotypic expression analysis revealed 20 MUC2-positive tumors(42.6%),11 MUC5AC-positive(23.4%),4 MUC6-positive(8.5%),and 7 CD10-positive(14.9%).The tumor sizes of the MUC2(+) tumors were significantly larger than those of the MUC2(-) tumors(mean,5.7 ± 1.4 cm vs 4.7 ± 2.1 cm,P < 0.05).All three tumors with adenomatous component were positive for MUC2(P < 0.05).Polypoid appearance was seen significantly more frequently in the CD10(+) group than in the CD10(-) group(P < 0.05).The tumor size was significantly larger in the CD10(+) group than in the CD10(-) group(mean,5.9 ± 1.4 cm vs 5.0 ± 2.1 cm,P < 0.05).Of 34 SIAs with successfully obtained MSI data,4 were MSI-high.Of the 4 SIAs positive for both MUC5 AC and MUC2,3 showed MSI-H(75%) and 3 were mucinous adenocarcinoma(75%).KRAS mutations were detected in 4 SIAs.SIAs had KRAS mutation expressed only MUC2,but were negative for MUC5 AC,MUC6 and CD10.CONCLUSION:These findings suggest that the phenotypic expression of SIAs is correlated with their biological behavior,genetic alteration,and MSI status.

Comparison between colorectal low- and high-grade mucinous adenocarcinoma with MUC1 and MUC5AC

AIM:To explore useful prognostic factors for mucinous adenocarcinoma(MAC) in the colon and rectum.METHODS:MAC was divided into low-and high-grade types based on the degree of structural differentiation;low-grade MAC arisen from well to moderately differentiated adenocarcinoma and papillary carcinoma,and high-grade MAC from poorly differentiated adenocarcinoma and signet ring cell carcinoma.Immunohistochemically,the expression of 2 types of MUC1(MUC1/DF and MUC1/CORE),MUC2,2 types of MUC5AC(MUC5AC/CHL2 and HGM),MUC6,CDX2,and CD10 was examined in 16 cases of MAC consisting of 6 low-and 10 high-grade types.RESULTS:MUC1/DF3 was expressed in 3 of 6 low-grade MAC(50) and 10 of 10 high-grade MAC(100).MUC1/CORE was expressed in 1 of 6 lowgrade MAC(16.7) and 7 of 10 high-grade MAC(70).MUC2 was expressed in all MAC regardless of the grade.MUC5AC was expressed in 6 of 6 low-grade MAC(100) and 4 of 10 high-grade MAC(40).HGM was expressed in 5 of 6 low-grade MAC(83.3) and 6 of 10 high-grade MAC(60).Expression of MUC6 and CD10 was undetected in all MAC regardless of the grade.CDX2 was expressed in 5 of 6 low-grade MAC(83.3) and 7 of 10 high-grade MAC(70).Taken together,MUC1/DF3 was expressed significantly more frequently in high-grade MAC than in low-grade,and MUC5AC/CHL2 was expressed significantly more frequently in low-grade MAC than in high-grade.CONCLUSION:It is proposed that MUC1/DF3 and MUC5AC/CHL2 immunostaining is useful to discriminate high-grade MAC from low-grade MAC.

Cystic metastasis from a mucinous adenocarcinoma of duodenum mimicking type Ⅱ choledochal cyst: A case report

A 51-year-old male patient was referred to our hospital because of an incidentally detected cystic mass near the common bile duct(CBD). Imaging studies demonstrated a cystic mass that was suspected to communicate with the CBD. Gastroscopy showed irregular mucosal thickening with hyperemic change in the second portion of the duodenum. A type Ⅱ choledochal cyst combined with duodenal malignancy was suspected. The patient underwent surgical resection and the histological diagnosis was mucinous adenocarcinoma of the duodenum with cystic metastasis. Although its incidence is extremely rare, care should be taken to check for other sites of malignancy when a pericholedochal cystic mass is detected.

Concomitant pancreatic adenocarcinoma in a patient with branch-duct intraductal papillary mucinous neoplasm

Branch duct intraductal papillary mucinous neoplasms(BD-IPMN) are pre-malignant pancreatic cystic lesions which carry a small risk of malignant transformation within the cyst. Guidelines exist with respect to surveillance of the cysts using computed tomography, magnetic resonance imaging, and/or endoscopic ultrasound(EUS). There are reports that patients with IPMNs are at increased risk of developing pancreatic adenocarcinoma, which arises in an area separate to the IPMNs. We present two cases of pancreatic adenocarcinoma arising within the parenchyma, distinct from the IPMN-associated cyst, identified with EUS. This case report highlights that patients with BD-IPMN are at increased risk for pancreatic adenocarcinoma separate from the cyst and also the importance for endosonographers to carefully survey the rest of the pancreatic parenchyma separate from the cyst in order to identify small pancreatic adenocarcinomas.

Malignant transformation of pulmonary bronchiolar adenoma into mucinous adenocarcinoma:A case report

BACKGROUND Bronchiolar adenoma(BA)and ciliated muconodular papillary tumor are rare tumors that have bilayered cell proliferation and continuous expression of p40 and CK5/6 in the basal cell layer.Diagnosis is difficult because of the limited knowledge of these tumors and their morphological similarities to malignant tumors,including invasive mucinous adenocarcinoma,especially based on the histopathology of intraoperative frozen sections.These tumors are now considered to be benign neoplasms,with malignant transformation reported in only a few cases.CASE SUMMARY A 57-year-old woman presented with a 17.0 mm×7.0 mm nodule in the lower lobe of the left lung.Hematoxylin-eosin staining and immunohistochemistry of a surgical specimen were performed.The tumor consisted of a BA area and a mucinous adenocarcinoma(MA)area.In the BA area,the tumor had a bilayered structure of luminal cells and basal cells.The basal cells were positive for CK5/6 and p40,but the MA area was negative for these biomarkers.The Ki-67 proliferation index was low(1%-2%).The patient was diagnosed with BA accompanied by MA,and had a favorable outcome.CONCLUSION The present study indicated that BA may be carcinogenic,and suggests that clinicians should be aware of its potential for malignant transformation.

The development and implementation of pathological parameters and molecular testing impact prognosis of colorectal adenocarcinoma

Objective:This study aims to analyze how changes in pathological diagnosis practice and molecular detection technology have affected clinical outcomes for colorectal cancer(CRC)patients in Fudan University Shanghai Cancer Center(FUSCC).Methods:This retrospective cohort study analyzed 21,141 pathologically confirmed CRC cases diagnosed at FUSCC from 2008 to 2020.Patients were divided into five groups for different analytical purposes:(1)the before vs.since 2014 groups to analyze the influence of the changes in the classification criteria of pT3 and pT4 staging on the survival of patients;(2)the partial vs.total mesorectal excision(TME)groups to analyze whether evaluation of completeness of the mesorectum have impact on the survival of patients;(3)the tumor deposit(TD)(+)N0 vs.TD(+)N1c groups to analyze the influence of the changes in the pN staging on the survival of patients with positive TD and negative regional lymph node metastasis(LNM);(4)the before vs.since 2013 groups to analyze the influence of the changes in the testing process of deficient mismatch repair on the survival of patients;and(5)the groups with vs.without RAS/BRAF gene mutation testing to analyze the influence of these testing on the survival of patients.Patients’clinicopathological parameters,including age at diagnosis,sex,tumor size,location,differentiation,mucinous subtype,TD,lymphovascular invasion,perineural invasion,tumor depth,LNM and distant metastasis,and tumor-node-metastasis(TNM)stage,were compared between groups.Kaplan-Meier analysis with log rank method was performed for patients’overall survival(OS)and disease-free survival(DFS)analyses.Results:In pathological reports,there were three parameter changes that impacted patient outcomes.Firstly,changes in the pT staging criteria led to a shift of the ratio of patients with stage pT3 to stage pT4 from 1:110.9 to 1:0.26.In comparison to patients admitted before 2014(n=4,754),a significant difference in prognosis between pT3 and pT4 stages was observed since 2014(n=9,965).Secondly,we began to evaluate the completeness of the mesorectum since 2016.As a result,91.0%of patients with low rectal cancer underwent TME(n=4,111)surgery,and patients with TME had significantly better OS compared with partial mesorectal excision(PME,n=409).Thirdly,we began to stage TD(+)LNM(-)as N1c since 2017.The results showed that N1c(n=127)but not N0(n=39)can improve the prognosis of patients without LNM and distal metastasis.In molecular testing,there have been three and five iterations of updates regarding mismatch repair(MMR)/microsatellite instability(MSI)status and RAS/BRAF gene mutation detection,respectively.The standardization of MMR status testing has sharply decreased the proportion of deficient MMR(dMMR)patients(from 32.5%to 7.4%)since 2013.The prognosis of patients underwent MMR status testing since 2013(n=867)were significantly better than patients before 2013(n=1,313).In addition,detection of RAS/BRAF gene mutation status(n=5,041)resulted in better DFS but not OS,for patients with stage I-III disease(n=16,557).Conclusion:Over the past few decades,updates in elements in pathological reports,as well as the development of standardized tests for MMR/MSI status and RAS/BRAF gene mutations have significantly improved patient outcomes.

Double-mutant invasive mucinous adenocarcinoma of the lung in a 32-year-old male patient:A case report

BACKGROUND Invasive mucinous adenocarcinoma of the lung,formerly known as mucinous bronchioloalveolar carcinoma,is a rare category of lung tumors and radiologically characterized by dense pneumonic consolidation,ground-glass opacity,crazy paving,and nodules.However,early pleural effusion is uncommon in this malignancy.CASE SUMMARY The case of a 32-year-old male patient who visited our facility with symptoms of cough and gradually aggravated shortness of breath was reported.X-ray examination revealed a massive left hydrothorax.The patient underwent thoracocentesis,and pleural fluid tumor markers,including carcinoembryonic antigen,carbohydrate antigen 19-9,neuron-specific enolase,and cytokeratin 21-1 fragment,were significantly elevated.A similar tendency was observed among the serum tumor markers.After draining the pleural effusion,the patient underwent chest computed tomography,and no obvious mass was found in the lung.Thoracoscopy revealed that the left visceral pleura was covered with nodular,cauliflower-like protrusions of various sizes.These histopathological results suggested cancerous cells,and the immunohistochemical findings were consistent with mucinous adenocarcinoma of pulmonary origin.It tested positive for cytokeratin,cytokeratin 5/6,carcinoembryonic antigen,and thyroid transcription factor-1.CONCLUSION The patient was diagnosed with a rare case of lung mucinous adenocarcinoma.Subsequent genetic testing was positive for epidermal growth factor receptor-21 mutations and echinoderm microtubule-associated protein-like 4-lymphoma anaplastic kinase fusion.This prompted treatment with alfatinib and crizotinib.

Mucinous adenocarcinoma of the buttock associated with hidradenitis:A case report

BACKGROUND Mucinous adenocarcinomas of the buttock are rare and have an uncertain etiology and natural course.They are usually related to chronic anal fistulas,hidradenitis suppurativa,or Crohn's disease.Here,we report a case of mucinous adenocarcinoma associated with hidradenitis and contradictory immunochemistry results.CASE SUMMARY A 62-year-old man complained of recurrent abscesses of the buttock for 3 years.He had several scars and nodules in bilateral buttocks,with purulent discharge.The skin lesions did not appear to originate from the anus.The patient was diagnosed with recurrent abscesses due to hidradenitis suppurativa at the first visit.He showed purulent and subsequent mucin discharge in the first operation and was diagnosed with mucinous adenocarcinoma.Several examinations were performed to determine disease origin and staging.There were no significant findings or evidence of anal fistulas.Hence,he underwent wide local excision and V-Y advancement flap in the second operation.The final diagnosis was mucinous adenocarcinoma without any evidence of anal fistulas.Additional immunochemistry test results were negative for cytokeratin(CK)7 and positive for CK20 and CDX2,with a colorectal origin.A pathologist suggested that the disease originated from a chronic anal fistula.The patient has remained free of recurrence for 24 mo.CONCLUSION Although the patient with mucinous adenocarcinoma showed an atypical course,immunochemistry helped detect the disease origin.

Delayed diagnosis of ascending colon mucinous adenocarcinoma with local abscess as primary manifestation: Report of three cases

BACKGROUND Colorectal mucinous adenocarcinoma is a distinct subtype of colorectal adenocarcinoma that is not sensitive to chemotherapy and radiotherapy,and its prognosis is worse than that of nonmucinous adenocarcinoma.Early diagnosis and aggressive surgical treatment may be the key to improving the prognosis of patients.Ascending colon mucinous adenocarcinoma with the primary manifestation of a local abscess caused by non-intestinal perforation has never been reported.Moreover,since the lumen of the ascending colon is large,and early stage ascending colon cancer lacks typical clinical manifestations,the diagnosis may be delayed easily.We herein report three cases of delayed diagnosis of colorectal mucinous adenocarcinoma.CASE SUMMARY We present three patients(two females and one male)with mucinous ascending colon mucinous adenocarcinoma with the primary manifestation of a local abscess(the right area of the lumbar spine,right groin,and lower right abdomen)caused by non-intestinal perforation.At the initial clinical visit,the common causes of those abscesses,including spinal tuberculosis and urinary tract infection,were excluded.The treatment of the abscess was through an incision and drainage.However,the source of the abscess was not made clear,which led to an abscess recurrence and a delayed diagnosis of colorectal mucinous adenocarcinoma.After the patients were referred to our hospital,a definitive diagnosis of ascending colon mucinous adenocarcinoma was made with the help of tumor markers and colonoscopic findings.Because of the delayed diagnosis of the disease,two patients(case 1 and case 2)missed the chance of surgery due to disease progression and died in a short follow-up period.Only case 3 underwent radical surgery for the tumor in the right colon and partial abdominal wall resection and achieved a better prognosis.CONCLUSION Abscesses in the right area of the lumbar spine,right groin,or right lower quadrant caused by non-intestinal perforation as the primary clinical manifestation of ascending colon mucinous adenocarcinoma are extremely rare.Mucinous adenocarcinoma of the ascending colon may be one of the causes of such abscesses.Performing colonoscopy as soon as possible is of great significance in the diagnosis and treatment of the disease.

Mucinous adenocarcinoma arising from a tailgut cyst: A case report

BACKGROUND Retrorectal hamartomas or tailgut cysts(TCs)are rare.In most cases,they are asymptomatic and benign;however,rarely,they undergo malignant transformation,mainly in the form of adenocarcinoma.CASE SUMMARY A 55-year-old woman presented to our hospital with lower back pain.On magnetic resonance imaging,a large pelvic mass was found,which was located on the right of the ischiorectal fossa,extending to the minor pelvis.The patient underwent extensive surgical resection of the lesion through the right buttock.Histological examination confirmed the diagnosis of a retrorectal mucinous adenocarcinoma originating from a TC.Surgical resection of the tumour was complete,and the patient recovered without complications.The pilonidal sinus was then excised.One year later,semi-annual positron emission tomographycomputed tomography and magnetic resonance imaging scans did not reveal any evidence of local recurrence or metastatic disease.CONCLUSION Preoperative recognition,histological diagnosis,and treatment of TCs pose significant challenges.In addition,the possibility of developing invasive mucinous adenocarcinoma,although rare,should be considered.