Primary cutaneous diffuse large B-Cell lymphoma, leg type mimicking subcutaneous panniculitis-like T-cell lymphoma in a COVID-19 setting: case report and review of literature.

ABSTRACT

Primary cutaneous diffuse large B-cell lymphoma, leg type is a rare entity accounting for 4% of all primary cutaneous lymphomas whose clinical presentation encompasses a range of possibilities. COVID-19 has caused a delay in diagnosis of malignant neoplasms and consequently, this has resulted in poorer prognoses. A 62-year-old woman presented with two smooth-surfaced, mobile, well-circumscribed, oval, skin-colored nodules approximately one-cm in diameter with nonerythematous borders on the lower third of the left leg. Two months later, eleven nodules measuring between one and 1.5cm with erythematous halo, slight scaling, central erosion, and crusting had appeared. Histological study showed moderate pericapillary lymphocytic infiltration in the papillary and reticular dermis and prominent diffuse proliferation of medium to large cells in the subcutis. These exhibited irregular vesicular nuclei, a conspicuous solitary nucleolus of two to three small nucleoli, and three mitoses per high power field. Adipocytes were consistently encircled by neoplastic lymphocytes. Primary cutaneous diffuse large B-cell lymphoma, leg type is a high-grade lymphoma that can manifest as a diagnostic challenge and requires adequate immunohistochemistry and in situ hybridization studies for proper diagnosis, treatment, and prognosis.