Thoracic subcutaneous infiltration: an unusual presentation of subcutaneous panniculitis-like T-cell lymphoma.

Sir, Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is an uncommon type of peripheral T-cell lymphoma. The classical clinical presentation is erythematous, subcuta-neous plaques or nodules involving the extremities and the trunk. Two distinctive entities are described: SPTCL with α/β or γ/δ phenotype. We report here an atypical clinical presentation of SPTCL, illustrating the difficulties of diagnosis of this kind of T-cell lymphoma. A 54-year-old man, with no medical history, was referred for evaluation of an erythematous, oedematous subcutaneous infiltration of the trunk. The symptoms had begun 2 months earlier with numerous, tender, erythematous nodules of the trunk, associated with fever up to 39°C that persisted despite antibiotics. Very quickly, the cutaneous symptoms changed into an erythematous, oedematous thickening of the skin of the trunk with no visible nodules (Fig. 1). This was associated with a weight gain of 10 kg. No lymphadenopathy was found. Laboratory studies revealed anaemia (haemoglobin: 10 g/dl), elevated liver function test findings (serum glutamate oxaloacetate transaminase: 156 UI/l; serum glutamate pyruvate transaminase: 128 UI/l; normal value < 30 UI/l), elevated lactic dehydroge-nase (LDH) 1707 UI/l (normal < 420 UI/l), hyperferritinaemia 13,946 µg/l (normal < 80 µg/l) and hypertriglyceridaemia 5.61 g/l (normal < 1.7g/l). Immunological and bacteriological laboratory studies and viral serologies were all negative. Several punch biopsies were performed. In each of these the epidermis showed reactive changes, with no epidermotropism, associated with a mild dermal inflammatory infiltrate simulating pannicu-litis. However, the biopsies were too superficial to conclude. A thoracic/abdominal computed tomography (CT) scan showed a diffused subcutaneous thoracic and abdominal wall infiltration, hepatosplenomegaly without deep lymphadenopathy (Fig. 2a). Bone marrow biopsy did not show haemophagocytosis or involve ment by lymphoma. A deep incisional biopsy specimen of the abdominal infiltration was performed. It displayed aggregates of foamy histiocytes and lymphocytes extending into subcutaneous fat associated with necrosis and karryorrhexis (Fig. 3a). The infiltrate was mild and consisted of small, medium and large lymphoid cells with irregular nuclear contour and densely clumped chromatin. These atypical lymphocytes were rimming fat lobules. Immunophenotypical analysis in paraffin sections showed that the neoplastic cells were of T-cell phenotype, stained with CD45, CD3, and CD8, but CD56-and CD30-negative. In addition, there was CD7 antigen loss. CD68+ staining revealed the presence of histiocytes. Molecular biological studies (polymerase chain reaction (PCR)) of α/β T cell receptor (TCR) in the skin and the blood revealed clonal T-cell population. Immunohistochemistry studies using anti-human α/β TCR and anti-human …