A rare case of fever of unknown origin: subcutaneous panniculitis-like T-cell lymphoma (SPTCL).

A 26-year-old man presented with high-grade fever, chills, productive cough and episodic abdominal pain of 6 months duration. Physical examination revealed that the patient was febrile and had multiple, ill-defined, tender, indurated, erythematous nodules and plaques over the trunk and thighs. Systemic examination and investigations revealed bilateral exudative pleural effusion with an increased adenosine deaminase (ADA) level. Pulmonary tuberculosis was suspected and the patient was started on a standard four-drug antitubercular regimen. Since his fever persisted, biopsy of the plaque over the trunk was performed, which showed lobular panniculitis with atypical lymphoid cells. Immunohistochemistry showed atypical lymphoid cells, which were CD3 and CD8 positive and CD4 negative. Based on the clinical features, skin biopsy and immunohistochemistry, the diagnosis of subcutaneous panniculitis-like T-cell lymphoma was made. The patient was treated with chemotherapy followed by bone marrow transplantation, and 4-year follow-up showed complete remission of lymphoma.