BACKGROUND: Marginal zone lymphoma (MZL) is an indolent non-Hodgkin B cell lymphoma with various architectural pattern including perifollicular, follicular colonization, nodular, micronodular, and diffuse patterns. A sclerotic variant has not been previously reported and represents a diagnostic pitfall.
METHODS: A 66-year-old male developed left upper extremity swelling. Chest computed tomography (CT) in September 2020 showed 14 cm mass in left axilla. Needle core biopsy of axillary lymph node showed sclerotic tissue with atypical B lymphoid infiltrate but was non-diagnostic. Excisional biopsy was performed for diagnosis and showed extensive fibrosis and minor component of infiltrating B cells. Flow cytometry showed a small population of CD5-, CD10-, kappa restricted B cells. Monoclonal immunoglobulin heavy chain and light chain gene rearrangement were identified. Upon being diagnosed with MZL, patient was treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone and achieved complete remission by positron emission tomography/CT.
CONCLUSIONS: This is an important case report because by morphology this case could have easily been overlooked as non-specific fibrosis with chronic inflammation representing a significant diagnostic pitfall. Moreover, this constitutes a new architectural pattern. While sclerotic lymphomas have rarely been described (often misdiagnosed as retroperitoneal fibrosis), we do not know of any cases describing this architectural presentation of MZL.

A very unusual radiographic presentation of non-Hodgkin lymphoma (NHL) involving the maxilla is described. The patient was initially managed with antibiotics prescribed to treat what was thought to represent an odontogenic infection. After unsuccessful antibiotic therapy, the patient was referred to an oral surgery clinic where CBCT was performed. CBCT revealed an atypical generalized sclerosis of the affected bone rather than the usual lytic radiographic pattern associated with NHL. Destruction of the sinus floor with infiltration of the sinus was also present. This rare radio-opaque radiographic presentation is described in detail together with the clinical presentation and histopathological findings. The important radiographic features suggesting malignancy that were present in this atypical case of NHL are discussed. A differential diagnosis highlighting the differences between NHL, osteomyelitis and osteosarcoma is also provided.