Peripheral T-cell lymphoma with secondary epithelioid granulomatous cutaneous involvement: a clinicopathologic study of four cases.

Epithelioid granuloma formation has rarely been observed in specific cutaneous lesions from T-cell lymphomas other than those of mycosis fungoides/Sézary syndrome (MF/SS). Three patients diagnosed with nodal and/or extranodal (tonsillar) non-Hodgkin's peripheral T-cell lymphoma (PTCL) and one patient with angioimmunoblastic T-cell lymphoma (AILD), developed specific cutaneous involvement showing prominent epithelioid cell and/or granulomatous inflammation. The original diagnostic lesions had no granulomatous features. In addition to a specific lymphomatous infiltrate, prominent dermal and/or subcutaneous granulomatous infiltrates were observed. Sarcoid-like granulomas were observed in two patients (one of them presented a granuloma annulare-like pattern in early lesions), granulomatous panniculitis was noted in one patient and in one patient with AILD, masses of epithelioid cells were noted. The clinicopathological features of cutaneous involvement by PTCL showing a florid epithelioid and/or granulomatous cell reaction are reviewed. Various histopathological patterns can be observed. The diagnostic difficulties of these cases are stressed.