Primary Lymphoma of Bone: Imaging Findings to Improve Diagnosis of a Rarely Considered Disease Prior to Biopsy

Objective: Primary lymphoma of bone (PLB) is a rare malignant bone tumor often presenting in the fifth-sixth decades involving appendicular long bones. Published radiological findings indicate that PLB typically presents as a moth-eaten osteolytic lesion with periosteal reaction, while MRI commonly demonstrates marrow infiltration with extraosseous extension. Given rarity and variable appearances, PLB may not be primarily considered prior to biopsy. Our objective was to evaluate preoperative imaging findings in effort to increase awareness and improve a perceived deficiency in preoperative diagnosis. Materials and Methods: Following IRB approval, retrospective review identified 60 patients with newly diagnosed bone lesions proven to represent PLB in accordance with WHO definition. Preoperative radiographs (n = 46), MRI (n = 33) and PET (n = 37) were independently reviewed by two radiologists. At radiography, lesions were classified: purely lytic, mixed, purely sclerotic, or occult;lytic lesions were graded utilizing Lodwick’s classification. At MRI, lesions were defined as focal or infiltrative and the presence or absence of extraosseous disease was recorded. Extraosseous masses were defined as small (1 cm) and subjectively correlated with degree of cortical destruction. At PET, lesions were recorded as FDG-avid or not. Primary radiograph reports when available (n = 33) were reviewed and exact wording of differential considerations was recorded. Results: Radiographs demonstrated mixed (n = 22), lytic (n = 15), and sclerotic (n = 8) appearances;one radiographically occult lesion was seen by MRI. Lytic lesions were graded: IB (n = 3), IC (n = 5), II (n = 4), and III (n = 3);none were IA. At MRI, 30 lesions were infiltrative and 3 were focal;11 were not associated with extraosseous extension, while 22 showed bony disease with small (n = 7) or large (n = 15) soft tissue mass. Of large masses, 13 demonstrated minimal cortical destruction. At PET, 36 demonstrated FDG uptake;one study was technically limited. Review of reports found that only 5 included “lymphoma” as a diagnostic consideration. Conclusion: Contrary to most published data, we suggest that PLB typically demonstrates some degree of osteosclerosis, often a mixed pattern of sclerosis and lucency;purely lytic lesions may be less common. Similar to existing reports, MRI commonly demonstrates marrow infiltration with extraosseous extension of disease, typically a large soft tissue mass with disproportionate (minimal) cortical destruction. Familiarity with these findings should improve preoperative consideration of PLB in the appropriate clinical scenario when a new osteoblastic lesion is identified.

Management of synchronous lateral pelvic nodal metastasis in rectal cancer in the era of neoadjuvant chemoradiation: A systemic review

BACKGROUND Lateral pelvic lymph node(LLN)metastasis(LLNM)occur in up to 28%of patients with low rectal tumours.While prophylactic lateral pelvic lymph node dissection(LLND)has been abandoned by most western institutions in the era of neoadjuvant chemoradiation therapy(CRT),the role of selective LLND in patients with enlarged LLN on pre-CRT imaging remains unclear.Some studies have shown improved survival and recurrence outcomes when LLNs show"response"to CRT.However,no management algorithm exists to differentiate treatment for"responders"vs"non-responders".AIM To determine if selective LLND in patients with enlarged LLNs results in improved survival and recurrence outcomes.METHODS A systemic search of Pub Med and Embase databases for studies reporting on patients with synchronous radiologically suspicious LLNM(s-LLNM)in rectal cancer receiving preoperative-CRT was performed.RESULTS Fifteen retrospective,single-centre studies were included.793 patients with sLLNM were evaluated:456 underwent TME while 337 underwent TME with7,LLND post-CRT.In the TME group,local recurrence(LR)rates range from 12.5%to 36%.Five-year disease free survival(DFS)was 42%to 75%.In the TME with LLND group,LR rates were 0%to 6%.Five years DFS was 41.2%to 100%.Radiological response was seen in 58%.Pathologically positive LLN was found in up to 94%of non-responders vs 0%to 20%in responders.Young age,low tumour location and radiological non-response were associated with final positive LLNM and lowered DFS.CONCLUSION LLND is associated with local control in patients with s-LLNM.It can be performed in radiological non-responders given a large majority represent true LLNM.Its role in radiological responders should be considered in selected high risk patients.

Gastrointestinal stromal tumor and its targeted therapeutics

Over the past 60 years,investigators of basic science,pathology,and clinical medicine have studied gastrointestinal stromal tumor(GIST) and made minor advances in patient care.Recent discoveries have led to an understanding of the biological role of KIT and platelet-derived growth factor receptor-α in GIST and the development of the tyrosine kinase inhibitor imatinib mesylate(Gleevec,formerly STI-571),one of the most exciting examples of targeted therapy to date.The success of targeted therapy in GIST has lead to new developments in our understanding of the medical and surgical management of the disease.Intense study of GIST may lead to new paradigms in the management of cancer.

Understanding sarcoma drug resistance one cell at a time

As true for any cancer,intrinsic and acquired drug resistance represent perhaps the single biggest obstacle limiting our ability to cure patients with metastatic disease.Yet,tackling this challenge has been particularly difficult for sarcoma.First and foremost,sarcomas are rare and diverse,which splits a class of tumors representing less than 1 percent of all malignancies into more than fifty smaller molecularly and histologically distinct entities,each having its own etiology,prognosis,and clinical presentation.Even the most“common”sarcoma subtypes(e.g.,liposarcoma,leiomyosarcoma,or gastrointestinal stromal tumors)have annual incidences in the thousands in the United States,whereas rarer subtypes like desmoplastic small round cell tumors number less than fifty per year.Due to their scarcity,it’s not uncommon for just a few cell lines,organoids,or patient-derived tumor explants to exist for each sarcoma subtype.This shortage limits their usefulness to model the wide variety of innate and adaptive mechanisms that exist in human tumors.Many times,no representative preclinical model exists.The scarcity of FDA-approved drugs aimed at sarcoma-specific targets,often fusion proteins and transcription factors,is also problematic.