Avoiding misdiagnosis of multilocular thymic cysts as malignant tumors on computer tomography

This editorial provides insights from a case report by Sun et al published in the World Journal of Clinical Cases.The case report focuses on a case where a multilocular thymic cyst(MTC)was misdiagnosed as a thymic tumor,resulting in an unnecessary surgical procedure.Both MTCs and thymic tumors are rare conditions that heavily rely on radiological imaging for accurate diagnosis.However,the similarity in their imaging presentations can lead to misinterpretation,resulting in unnecessary surgical procedures.Due to the ongoing lack of comprehensive knowledge about MTCs and thymic tumors,we offer a summary of diagnostic techniques documented in recent literature and examine potential causes of misdiagnosis.When computer tomography(CT)values surpass 20 Hounsfield units and display comparable morphology,there is a risk of misdiagnosing MTCs as thymic tumors.Employing various differential diagnostic methods like biopsy,molecular biology,multi-slice CT,CT functional imaging,positron emission tomography/CT molecular functional imaging,magnetic resonance imaging and radiomics,proves advantageous in reducing clinical misdiagnosis.A deeper understanding of these conditions requires increased attention and exploration by healthcare providers.Moreover,the continued advancement and utilization of various diagnostic methods are expected to enhance precise diagnoses,provide appropriate treatment options,and improve the quality of life for patients with thymic tumors and MTCs in the future.continued advancement and utilization of various diagnostic methods are expected to enhance precise diagnoses,provide appropriate treatment options,and improve the quality of life for patients with thymic tumors and MTCs in the future.

Misdiagnosis of Sexually Transmitted Diseases in Hong Kong Outpatient Private Healthcare

Background and objective: Early and accurate diagnosis is one of the critical requirements for successful management of all diseases. Yet, delayed diagnosis and misdiagnosis remain as vital problems, consequently impose adverse effects on patient treatment. Sexually transmitted disease (STD) is one of the most common infectious diseases, and more than one million of STD cases are acquired every day globally. Misdiagnosis of STD inevitably exists, therefore should not be overlooked. Being a medical diagnostic laboratory providing various STDs diagnosing service in Hong Kong, we aimed to determine the misdiagnosis rate of STDs and investigate the possible underlying cause. Methods: Specimens were collected for STD diagnosis from multiple clinics during 1 June 2021 to 20 October 2021 from different clinics and hospitals were included in the study. DNA extraction was performed using magnetic bead based method;then the extracted DNA was tested using the DiagCor GenoFlowTM STD Array kit to detect the existence of any targeted pathogens. Results: 1459 specimens were collected and included during the designated time period, with 643 specimens found to be positive with at least one targeted STD pathogen. 494 of these were found to be aligned with test ordered by physicians, and the remaining 149 positive cases had at least one pathogen detected but not requested to be tested by the physicians resulting in misdiagnosis. The overall misdiagnosis rate was determined to be 23.2% (149/643), with high frequency of misdiagnosis occurred to tests ordered for one to three pathogens detection. Also, Ureaplasma urealyticum and/or Ureaplasma parvum (UU/UP) was the commonest pathogen detected in this study. Conclusion: The findings suggested incorrect test selection made by physicians was one of the major reasons of STDs misdiagnosis in outpatient settings. To reduce diagnostic errors in STD diagnosis, physicians are encouraged to select and request test that allow detection of multiple pathogens, as co-infection of multiple pathogens in STD patients is commonly observed. The correct selection of test would not only benefit the patient, but also the public health.

Misdiagnosis and Delayed Diagnosis for Ectopic and Heterotopic Pregnancies after In Vitro Fertilization and Embryo Transfer

This study examined the misdiagnosis and delayed diagnosis factors for ectopic pregnancy（EP） and heterotopic pregnancy（HP） after in vitro fertilization and embryo transfer（IVF-ET） in an attempt to reduce the diagnostic error. Clinical data of patients who underwent IVF-ET treatment and had clinical pregnancy from 12463 cycles were retrospectively analyzed. Their findings of serum β-hCG test and transvaginal ultrasonography were also obtained during follow-up. These patients were divided into two groups according to the diagnosis accuracy of EP/HP： early diagnosis and misdiagnosis/delayed diagnosis. The results showed that the incidence of EP and HP was 3.8%（125/3286） and 0.8%（27/3286） respectively for IVF/ICSI-ET cycle, and 3.8%（55/1431） and 0.7%（10/1431） respectively for frozen-thawed embryo transfer（FET） cycle. Ruptured EP occurred in 28 patients due to initial misdiagnosis or delayed diagnosis. Related factors fell in 3 categories：（1） clinician factors： misunderstanding of patients＇ medical history, insufficient training in ultrasonography and unawareness of EP and HP;（2） patient factors： noncompliance with medical orders and lack of communication with clinicians;（3） complicated conditions of EP： atypical symptoms, delayed elevation of serum β-hCG level, early rupture of cornual EP, asymptomatic in early gestation and pregnancy of unknown location. All the factors were interwoven, contributing to the occurrence of EP and HP. It was concluded that complicated conditions are more likely to affect the diagnosis accuracy of EP/HP after IVF-ET. Transvaginal ultrasonography should be performed at 5 weeks of gestation. Intensive follow-up including repeated ultrasonography and serial serum β-hCG tests should be performed in patients with a suspicious diagnosis at admission.

Magnetic resonance imaging features of minimal-fat angiomyolipoma and causes of preoperative misdiagnosis

BACKGROUND Minimal-fat angiomyolipoma(mf-AML)is often misdiagnosed as renal cell carcinoma before surgery.AIM To analyze the magnetic resonance imaging(MRI)features of mf-AML and the causes of misdiagnosis by MRI before operation.METHODS A retrospective analysis was performed on ten patients with mf-AML confirmed by surgical pathology,all of whom underwent preoperative MRI examination to analyze the morphological characteristics and MRI signals of the tumor.RESULTS MRI revealed a circular-like mass in 4/10(40%)patients,an oval mass in 6/10 patients(60%),a mass with a capsule in 9/10 patients(90%),and a mass with a lipid component in 7/10 patients(70%).The diameter of the masses in all ten patients was from 11 to 47 mm;the diameter was between 11 mm and 40 mm in 8/10(80%)patients and between 40 mm and 47 mm in 2/10(20%)patients.CONCLUSION An oval morphological characteristic is strong evidence for the diagnosis of mf-AML,while a capsule and lipids are atypical manifestations of mf-AML.

Two case reports and literature review for hepatic epithelioid angiomyolipoma: Pitfall of misdiagnosis

BACKGROUND Hepatic epithelioid angiomyolipoma(HEAML) is a rare liver disease and is easily misdiagnosed. Enhanced recognition of HEAML is beneficial to the differential diagnosis of rare liver diseases.CASE SUMMARY We presented two cases of HEAML in Changzheng Hospital, Naval Medical University, and then collected and analyzed all reports about HEAML recorded in PubMed, MEDLINE, China Science Periodical Database, and VIP database from January 2000 to March 2018. A total of 409 cases of HEAML in 97 reports were collected, with a ratio of men to women of 1:4.84 and an age range from 12 years to 80 years(median 44 years). Among the patients with clinical symptoms mentioned, 61.93%(205/331) were asymptomatic, 34.74%(115/331) showed upper or right upper quadrant abdomen discomfort, while a few of them showed abdominal mass, gastrointestinal symptoms, low fever, or weight loss. The misdiagnosis rate of HEAML was as high as 40.34%(165/409) due to its nonspecific imaging findings. Most of the tumors were solitary and round in morphology, with clear boundaries. Ultrasound scan indicated low echo with internal nonuniformity and rich blood supply in most cases. Computer tomography/magnetic resonance imaging enhanced scan showed varied characteristics. The ratio of fast wash-in and fast wash-out, fast wash-in and slow wash-out, and delayed enhancement was roughly 4:5:1. A definite diagnosis of HEAML depended on the pathological findings of the epithelioid cells in lesions and the expression of human melanoma black 45, smooth muscle actin,melanoma antigen, and actin by immunohistochemical staining. HEAML had a relatively low malignant rate of 3.91%. However, surgical resection was the main treatment for HEAML, due to the difficulty diagnosing before operation.CONCLUSION HEAML is a rare and easily misdiagnosed disease, and it should be diagnosed carefully, taking into account clinical course, imaging, pathological,and immunohistochemical findings.

Misdiagnosis of left supraclavicular lymph node metastasis of hepatocellular carcinoma:A case report

Left supraclavicular lymph node metastasis is a rare presentation of hepatocellular carcinoma (HCC).This phenomenon is easily neglected in the clinic.A 56-yearold man presented with HCC.On examination,a 1cm long left supraclavicular lymph node was palpated.Auxiliary examination indicated a lesion located in the right lobe of the liver.Fine needle aspiration cytology (FNAC) of the enlarged lymph node was performed;however,only necrosis was found.Hepatectomy was performed and HCC was confirmed by Hematoxylin-Eosin staining.However,14 d after surgery,significantly enlarged left supraclavicular lymph nodes,a new intrahepatic lesion,and pulmonary and mediastinal metastasis appeared.An excisional biopsy of the left supraclavicular lymph node was performed,and its findings confirmed metastatic HCC.The patient's HCC rapidly progressed and he died one month later.It is possible for HCC tometastasize to the left supraclavicular lymph node.Surgeons should always consider an overall physical examination.When left supraclavicular lymphadenopathy of unknown origin is encountered,FNAC should be performed initially.If the results are negative,an excisional biopsy and subsequent Positron emission tomography computed tomography scanning should be performed.These are very important for making the correct diagnosis and for selecting reasonable therapies.

Temporal trends in the misdiagnosis rates between Crohn's disease and intestinal tuberculosis

AIM To investigate the temporal trends in the misdiagnosis rate between Crohn's disease(CD) and intestinal tuberculosis(ITB) in South Korea. METHODS We retrospectively reviewed the medical records of patients managed for CD or ITB at Asan Medical Center, a tertiary referral hospital, Seoul, Korea between 1996 and 2014. The temporal trends in the misdiagnosis rates between the two diseases were analyzed. The demographic and clinical characteristics were compared between CD patients who were initially misdiagnosed as ITB(final CD group) and vice versa(final ITB group). Final diagnostic criteria for ITB and medication for CD before definite diagnosis of TB were also analyzed in final ITB group.RESULTS In total, 2760 patients were managed for CD and 772 patients for ITB between 1996 and 2014. As well, 494 of the 2760 CD patients(17.9%) were initially misdiagnosed as ITB and 83 of the 772 ITB patients(10.8%) as CD. The temporal trend in misdiagnosing CD as ITB showed a decrease(OR = 0.89, 95%CI: 0.87-0.91, P < 0.001), whereas the temporal trend in misdiagnosing ITB as CD showed an increase(OR = 1.06, 95%CI: 1.01-1.11, P = 0.013). Age at diagnosis, presenting symptoms, and proportion of patients with active/past perianal fistula and active/inactive pulmonary tuberculosis(TB) were significantly different between final CD group and final ITB group. Forty patients(48.2%) in final ITB group were diagnosed by favorable response to empirical anti-TB treatment. Seventeen patients(20.5%) in final ITB group had inappropriately received corticosteroids and/or thiopurines due to misdiagnosis as CD. However, there were no mortalities in both groups. CONCLUSION Cases of CD misdiagnosed as ITB have been decreasing, whereas cases of ITB misdiagnosed as CD have been increasing over the past two decades.

Key determinants of misdiagnosis of tracheobronchial tuberculosis among senile patients in contemporary clinical practice:A retrospective analysis

BACKGROUND Tracheobronchial tuberculosis(TBTB)is a common subtype of pulmonary tuberculosis.Concomitant diseases often obscure the diagnosis of senile TBTB.AIM To characterize senile patients with TBTB and to identify the potential causes of misdiagnosis.METHODS One hundred twenty patients with senile TBTB who were admitted to the Anhui Chest hospital between May 2017 and May 2019 were retrospectively analyzed.Patients were classified as diagnosed group(n=58)and misdiagnosed group(n=62).Clinical manifestations,laboratory results,radiographic data,and endoscopic findings were compared between the two groups.RESULTS Patients in the misdiagnosed group were most commonly diagnosed as pulmonary tuberculosis(non-TBTB,29/62,46.8%),general pneumonia(9/62,14.5%),chronic obstructive pulmonary disease(8/62,12.9%),and tracheobronchial carcinoma(7/62,11.3%).The time elapsed between disease onset and confirmation of diagnosis was significantly longer in the misdiagnosed group[median(first quartile,third quartile):6.32(4.94,16.02)mo vs 3.73(2.37,8.52)mo].The misdiagnosed group had lower proportion of patients who underwent bronchoscopy[33.87%(21/62)vs 87.93%(51/58)],chest computed tomography(CT)scan[69.35%(43/62)vs 98.28%(57/58)],and those who showed CT signs of tuberculosis[27.91%(12/62)vs 50%(29/58)]as compared to that in the diagnosed group(P<0.05).There were no significant between-group differences with respect to age,gender,occupation,clinical manifestations,or prevalence of comorbid chronic diseases(P>0.05).CONCLUSION Insufficient or inaccurate radiographic or bronchoscopic assessment was the predominant cause of delayed diagnosis of TBTB.Increased implementation and better interpretation of CT scan and early implementation of bronchoscopy can help reduce misdiagnosis of senile TBTB.

Erythrocytosis caused by giant chromophobe renal cell carcinoma:a case report indicating a 9.year misdiagnosis of polycythemia vera

Background:Erythrocytosis,a rare paraneoplastic syndrome,generally occurs in patients with clear cell renal cell carcinoma and has never been reported in patients with chromophobe renal cell carcinoma.Case presentation:We report a case of a young man suffering from a giant(22-cm) mass on his left kidney.Because of a history of polycythemia vera,the patient had been treated for the condition for 9 years.Radical nephrectomy was successfully performed,and the postoperative pathologic examination confirmed a diagnosis of chromophobe renal cell carcinoma.Unexpectedly,the symptom of erythrocytosis disappeared after the surgery.Further examination and analysis were performed,and we finally attributed his erythrocytosis to chromophobe renal cell carcinoma.Conclusions:Chromophobe renal cell carcinoma could cause erythrocytosis,but the clear-cut mechanism needs further research.Secondary erythrocytosis such as those related with renal tumors should be taken into consideration during the diagnosis of polycythemia vera.

Misdiagnosis of primary intimal sarcoma of the pulmonary artery as chronic pulmonary embolism: A case report

BACKGROUND Primary intimal sarcoma of the pulmonary artery is a rare malignant tumor originating from the pulmonary artery,which has a low incidence rate and is easily misdiagnosed as pulmonary embolism.There is no standard protocol for the treatment of primary intimal sarcoma of the pulmonary artery.CASE SUMMARY This study reports a patient with primary intimal sarcoma of the pulmonary artery who was admitted to our hospital in 2017.The clinical characteristics,diagnosis,treatment and outcome of the patient were retrospectively analyzed.The patient was a Chinese Han male aged 44 years.He had three consecutive episodes of syncope,and was thus admitted to a local hospital.Computed tomography pulmonary angiography showed multiple lesions with abnormal densities in the pulmonary trunk,left pulmonary artery,mediastinum and pericardium,which were consistent with recurrence after tumor resection.He underwent surgery,and was pathologically diagnosed with intimal sarcoma of the pulmonary artery.He relapsed 3 mo after surgery,and apatinib was administered.His condition was stable after 4 mo,with tolerable and controllable adverse reactions.He subsequently died 19 mo after surgery.CONCLUSION Primary intimal sarcoma of the pulmonary artery has no specific clinical or imaging manifestations.The diagnosis of this disease depends on histopathology and immunohistochemistry,and has a poor clinical prognosis.Surgical treatment is currently a favorable option for primary intimal sarcoma of the pulmonary artery,and targeted therapy may provide new insights for the development of effective treatment methods.

Misdiagnosis of Angina Pectoris Due to Severe Coronary Artery Disease: An Anecdotal Case

Background: Misdiagnosis of angina pectoris is not uncommon in athletes. Physicians can fail to make a correct clinical diagnosis if they don’t have the skills and experience needed to recognize this disease. Case Report: This case report describes an exertional angina misdiagnosis due to a severe coronary artery disease in a 50-year-old male athlete initially examined by both a general practitioner and a cardiologist. The athlete subsequently underwent physical examination in a sports cardiology medicine center where diagnosis of angina pectoris caused by severe mono-vessel coronary artery disease was made, requiring an angioplasty with stenting. Conclusions: Although most of the severe symptoms in a heart attack are hard to miss, sometimes in athletes angina pectoris is not readily recognized. However, this is dangerous and can lead to the sudden death of the athlete. Diagnosis must be timely and accurate, in order for the patient to receive the best prognosis.

Misdiagnosis Features of Ancient Clinical Records Based on Apriori Algorithm

Objective:To analyze misdiagnosis features in clinical cases of“Classified Medical Cases of Famous Physicians”and“Supplement to Classified Case Records of Celebrated Physicians.”Materials and Methods:Two hundred and five ancient misdiagnosed cases were analyzed in aspects of locations(exterior-interior type,qi-blood type and Zang‑Fu organs type)and patterns(heat-cold type and deficiency-excess type)by Apriori Algorithm Method.Results:The main types of misdiagnosis in those medical casesare as follows::Zang‑Fu location misjudgment,misjudging the interior as the exterior,misjudging deficiency pattern as excess pattern,and misjudging cold pattern as heat pattern.Among them,the most outstanding type is the misjudgment of deficiency–cold pattern as excess–heat pattern.Conclusions:(1)Accurate judgment of location and differentiation of deficiency and excess patterns are the key points in diagnosing the diseases correctly.The confusion of true deficiency–cold and pseudo‑excess–heat pattern should be taken seriously.(2)Data mining on ancient clinical cases offers a new methodology for assisting clinical diagnosis of traditional Chinese medicine.

Twenty years of misdiagnosis of schizophrenia in a patient with Dandy-Walker variant syndrome

SUMMARY Various case reports of patients with Dandy-Walker variant syndrome mimicking schizophrenia have been published in the last 20 years, suggest!ng that this neurodevelopment disorder should be part of the differential diagnosis for every patient with a first episode of psychosis. In this report, it is presented that a patient who was diagnosed and treated as a paranoid schizophrenic for 20 years and had four bone fractures secondary to ataxic gait impairment, before performing a neuroimaging examination that revealed Dandy-Walker variant syndrome.

Room for improvement: Patterns of referral misdiagnosis to a vascular anomalies center

Objective: Vascular anomalies are a diagnostic and therapeutic challenge. Errors in diagnosis lead to treatment delay, inappropriate interventions and prolonged suffering. The aim of this study was to analyze patterns of misdiagnosis among patients referred to a vascular anomalies center (VAC). This will better define the problem and may be used to refine and improve referral guidelines for patients with vascular anomalies. Patients and Methods: After IRB approval, we performed a single-center retrospective review of all patients referred to a vascular anomaly between January 1, 2008 and December 15, 2011. Evaluation of both referral and final diagnosis was made. Data regarding accuracy of diagnosis were determined and compared for both vascular tumors and malformations. Results: Mean age was 7.9 ± 7.7 (13 days - 66 years). 42% had a correct diagnosis at the time of referral. Vascular tumors were correctly diagnosed more often than vascular malformations (58% vs 38%). The most common misdiagnosis for infantile hemangioma (IH) was venous malformation (VM). The most common misdiagnosis for VM was IH. Nonspecific and historical terms such as “mass”, “lymphangioma”, and “cavernous hemangioma” frequently appear as the referral diagnosis. Conclusion: Referral misdiagnosis is common. IH and VM are frequently confused and if there is any uncertainty in the diagnosis, these patients should also be referred to a VAC, in addition to the more complicated anomalies. Outdated nomenclature remains prevalent and continued efforts should be made to adhere to International Society for the Study of Vascular Anomalies (ISSVA) classification. Improvements in diagnostic accuracy are likely to greatly improve patients’ care.

Fine needle aspiration analysis of misdiagnosis of 2 cases with skin singular leiomyoma

This article reported that 2 cases with skin singular leiomyoma confirmed by pathology were misdiagnosed by fine needle aspiration biopsy, and the combination analysis of clinical history and pathological features of cells was as follows.

Misdiagnosis of Left Supraclavicular Lymph Node Metastasis of Prostate Carcinoma: One Case Report and Literatures Review

IntroductionChina is a country with a low morbidity of prostate carcinoma. The incidence of prostate carcinoma in China is 1.6/100,000, which is much lower than the rate in the United States, i.e., 119.9/100,000. Due to changes of lifestyle and improved measurement of serum prostate specific antigen （PSA） over the past decades, the incidence of prostate carcinoma in China also showed a yearly increase. However, the misdiagnosis and mistreatment of this disease commonly occur. The aim of this study is to report the case of a patient with prostate carcinoma presenting asymptomatic but with left supraclavicular lymphadenopathy, and analyze the reasons of misdiagnosis and mistreatment.

Echocardiography in the diagnosis of Shone’s complex and analysis of the causes for missed diagnosis and misdiagnosis

BACKGROUND Shone’s complex is a rare syndrome characterized by congenital left heart defects that can differ among the patients.AIM To use echocardiography in the diagnosis of Shone’s complex and analyze the causes of missed diagnosis and misdiagnosis.METHODS This was a retrospective study of patients who underwent echocardiography and repair surgery from February 14,2008,to November 22,2019.The patients were followed once a year at the outpatient clinic after surgery.RESULTS Sixty-six patients were included.The patients were 2.7(0.8-5.6)years of age,and 54.5%were male.Ten(15.2%)had a history of heart surgery.The most common heart defect was the Annulo-Leaflet mitral ring(ALMR)(50/66,75.8%),followed by coarctation of the aorta(CoA)(43/66,65.2%).The patients had a variety of combinations of defects.Only two(3.0%)patients had all four defects.None of the patients had a family history of congenital heart disease.The preoperative echocardiographic findings were examined against the intraoperative findings.Echocardiography missed an ALMR in 31 patients(47.0%),a parachute mitral valve(PMV)in one patient(1.5%),subaortic stenosis in one patient(1.5%),and CoA in two patients(3.0%).CONCLUSION Echocardiography is an effective method to diagnose the Shone’s complex.Due to this disease’s complexity and interindividual variability, Improving the understanding of thedisease can reduce misdiagnosis and missed diagnosis.

Misdiagnosis of an elevated lesion in the esophagus:A case report

BACKGROUND Esophageal carcinosarcoma(ECS) is a rare biphasic tumor and a type of esophageal malignancy,which presents as protruding or elevated lesions.ECS patients are often not hospitalized until they have severe dysphagia.ECS is easily misdiagnosed as a benign tumor due to its atypical characteristics under endoscopy.With the popularization of endoscopic treatment,these patients are often referred to endoscopic treatment,such as endoscopic submucosal dissection(ESD).However,there is a lack of consensus on the endoscopic features and therapies for ECS.Here,we report a case of ECS and discuss the value of endoscopic diagnosis and therapeutic strategies.CASE SUMMARY A 63-year-old man was admitted to the hospital with dysphagia.During the endoscopic examination,an elevated lesion was found with an erosive and hyperemic surface covered with white pseudomembranous inflammation.Endoscopic ultrasonography(EUS),biopsies,and enhanced thoracic computed tomography were performed,suggesting that it was a benign lesion and located within the submucosal layer.This lesion was diagnosed as a fibrovascular polyp with a Paris classification of 0-Ip.The patient was then referred to ESD treatment.However,the post-ESD pathological and immunohistochemical study showed that this lesion was ECS with a vertical positive margin(T1b stage),indicating that we made a misdiagnosis and achieved a noncurative resection.Due to the potential tumor residue,additional open surgery was performed at the patient’s request.In the postoperative pathological study,no tumor remnants or metastases were discovered.The patient was followed for 1 year and had no recurrence.CONCLUSION ECS can be misdiagnosed at the initial endoscopy.EUS can help to identify the tumor stage.Patients with T1b stage ECS cannot be routinely referred to ESD treatment due to the high risk of metastasis and recurrence rate.

Hepatic angiomyolipoma-misdiagnosis as hepatocellular carcinoma:A report of 14 cases

Angiomyolipoma (AML) is a rare benign mesenchymal tumor of the liver, composed of a varying heterogeneous mixture of three tissue components: blood vessels, smooth muscle, and adipose cells. It has recently been proposed that the perivascular epithelial cell (PEC) is the common progenitor[1，2] Since its first description by Ishak in 1976[3], there have been more than 100 cases reported in the English literature[4-6]. With the advance of radiological techniques, many more tumors are being diagnosed by the means. But radiological findings of AML may only be suggestive of the lesion; its definitive diagnosis requires histological confirmation[9-19]. Some authors regard renal and hepatic AMLs, pulmonary and soft tissue lymphangiomyomatosis[2], pulmonary and pancreatic clear cell “sugar” tumor, and cardiac rhabdomyoma as closely related groups of tumors, based on their morphologic overlap and common immunoreactivity for HMB-45[l]. They show different microscopic appearances, however, according to their organ of origin. The goals of this study were to highlight more subtle morphology and to gain possible insights into the differential diagnosis that could provide important information about this disease.

Misdiagnosis of tuberculosis and the clinical relevance of nontuberculous mycobacteria in Zambia

Objective:To determine the accuracy of TB diagnosis of TB in Zambia in the era of increasing HIV prevalence.Methods:Sputum of the clinically diagnosed TB cases was additionally subjected to liquid culture and molecular identification.This study distinguished between TB cases confirmed by positive Mycobacterium tuberculosis(M.tuberculosis) cultures and mycobacterial disease caused by non-tuberculous mycobacteria(NTM).Results:Only 49% of the 173 presumptively diagnosed TB cases was M.tuberculosis cultured,while in 13% (22) cases,a combination of M.tuberculosis and NTM was found.In 18% of the patients only NTM were cultured.In 28% ,no mycobacteria was cultivable.HIV positive status was correlated with the isolation of NTM(P【0.05).Conclusions:The diagnosis of tuberculosis based on symptoms, sputum smear and/or chest X-ray leads to significant numbers of false-positive TB cases in Zambia,most likely due to the increased prevalence of HIV.The role of NTM in tuberculosislike disease also seems relevant to the false diagnosis of TB in Zambia.