Track

Case Reports

Abstract

A 29-year-old male with a complex past medical history of cyclic vomiting, psoriatic arthritis, and splenomegaly was admitted with fever, pancytopenia and acute on chronic liver failure after COVID-19 infection. He developed multiple erythematous subcutaneous nodules after G-CSF treatment, clinically suspicious for Sweet syndrome. Punch biopsies showed extensive necrosis and thrombi in the subcutaneous fat, initially concerning for an infection or unusual autoinflammatory condition. Some atypical lymphocytes were present at the periphery, prompting a panel of immunohistochemical stains that revealed a surprisingly dense, partially necrotic, CD3+, CD8+, TIA+, granzyme+, CD56-, BF1+, EBER negative infiltrate with rimming adipocytes by Ki-67+ cells. TCR gene rearrangement testing demonstrated a monoclonal T cell population in both biopsies. A bone marrow biopsy was negative. At the time of initial diagnosis, a workup for hemophagocytic lymphohistiocytosis (HLH) was negative. Testing for HAVCR2 mutation was negative. Interestingly, heterozygous variants of uncertain significance were identified in CARD14 (c1134C>G) and PRF1 (c272 C>T). CARD14 mutations have been described in psoriasiform dermatitis. PRF1 encodes perforin and mutations have been described in patients with HLH.  Functional studies have shown that this variant leads to protein misfolding and dysfunction, but its specific connection to SPTCL and HLH requires additional investigation. This patient's course was complicated by the subsequent development of HLH, monoclonal gammopathy of uncertain significance, and abdominal wall bleeding. While SPTCL often carries a good prognosis, the presence of HLH significantly decreases the 5-year survival rate, highlighting the need for timely diagnosis and treatment.