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.

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.

Adventitial Microcirculation Is a Major Target of SARS-CoV-2-Mediated Vascular Inflammation.

We report the case of a 77-year-old woman affected by coronavirus disease-19 (COVID-19) who developed an occlusive arterial disease of the lower limb requiring a left leg amputation. We studied the mechanisms of vascular damage by SARS-CoV-2 by means of a comprehensive multi-technique in situ analysis on the diseased popliteal arterial district, including immunohistochemistry (IHC), transmission electron microscopy (TEM) and miRNA analysis. At histological analyses, we observed a lymphocytic inflammatory infiltrate, oedema and endothelialitis of adventitial vasa vasorum while the media was normal and the intima had only minor changes. The vasa vasorum expressed the ACE2 receptor and factor VIII; compared with the controls, VEGFR2 staining was reduced. TEM analyses showed endothelial injury and numerous Weibel-Palade bodies in the cytoplasm. No coronavirus particle was seen. IL-6 protein and mRNA, together with miR-155-5p and miRs-27a-5p, which can target IL-6, were significantly increased compared with that in the controls. Our case report suggests an involvement of adventitial artery microcirculation by inflammation in the course of COVID-19. Without evident signs of current infection by SARS-CoV-2, endothelial cells show a spectrum of structural and functional alterations that can fuel the cardiovascular complications observed in people infected with SARS-CoV-2.