Subcutaneous nodules in a patient with diffuse large B‐cell lymphoma

An 80-year-old, Chinese male presented with multiple nontender, nonpruritic, skin-coloured subcutaneous nodules over the chest, back, left flank, thigh and right forearm that developed course of 2 months (Figure 1). There was no surface change overlying edge slipped away when palpated between fingers (positive slip sign). He previously diagnosed stage IVB diffuse large B-cell lymphoma (DLBCL) germinal centre (GCB)-like subtype where initial staging positron emission tomography/computed tomography (PET/CT) at point diagnosis revealed extensive supra- infra-diaphragmatic lymphadenopathy. Extranodal involvement noted in a scapula lytic foci lumbar nodule but there bone marrow on biopsy. Immunohistochemistry his lymph node tissue showed positive expression MYC, BCL2 BCL6 proteins. Fluorescence in-situ-hybridization negative for C-MYC, translocations. treated six cycles chemo-immunotherapy consisting rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone (R-CHOP) adjuvant radiotherapy to bulky abdominal nodes 30.6 Gy 17 fractions, as well high dose intrathecal (3.5 g/m2) methotrexate central nervous system (CNS) prophylaxis view risk CNS International Prognostic Index. achieved complete metabolic remission end treatment lapsed 10 after last cycle R-CHOP pulmonary vascular presenting exertional dyspnea secondary hypertension confirmed echocardiography heart coronary angiography. Flow cytometry both peripheral capillary blood sample taken during angiogram presence CD45+ B-cells absent light chain (pulmonary—CD45+/SSC-lo, peripheral—CD45+/SSC-int). Salvage therapy two dexamethasone, cytarabine cisplatin (R-DHAP) given plans autologous stem cell harvesting transplantation. Five weeks second R-DHAP, he non-tender mobile described above. Repeat PET/CT hypermetabolic lesions. A skin biopsy flank performed 2). Histology sheets atypical lymphoid cells irregular nuclear contours, coarse chromatin, prominent nucleoli mitoses infiltrating adipose tissue. They were diffusely CD79a, weakly CD20 3). Skin DLBCL can be primary or secondary, papules, plaques, tumours are usually erythematous.1, However, lesions mimicking lipomas less common. In above case, relapsed resembling lipomatosis. Subcutaneous “lipoma-like” have been reported an uncommon cutaneous manifestation DLBCL.3 our patient solely tissue; these small-sized not metabolically active PET/CT. This presents potential diagnostic pitfall since small lipomatous masses typical clinical imaging features may require determine their nature, especially if patients lack significant medical history.4 Possible differential diagnoses include epidermoid cysts, angiolipomas angiomyolipomas. The identification disease has prognostic importance higher international index score.5, 6 As such, suspicion is required evaluating new context DLBCL. All authors contributed equally this publication. thank Kong Bing Tan, Department Pathology, National University Singapore, reporting histology specimen providing images. study did receive any funding. declare conflict interest. manuscript written informed consent participation use de-identified, anonymized, aggregated data case details (including photographs) Ethical Approval: applicable. Data available request from authors.