T-cell rich angiomatoid polypoid pseudolymphoma: a novel cutaneous pseudolymphoma.

Cutaneous pseudolymphomas refer to a group of benign reactive T or B cell lymphoproliferative processes that simulate cutaneous lymphomas. T cell rich angiomatoid polypoid pseudo lymphoma (TRAPP) of the skin is a unique form of T cell rich cutaneous pseudolymphoma. A 13-year-girl presented with an asymptomatic skin colored papule on the right elbow, the biopsy of which revealed features consistent with TRAPP. The dermis showed an infiltrate of lymphocytes, plasma cells, and histiocytes along with prominent vascular channels lined by plump endothelium. An immunohistochemical study showed a predominance of T cells over B cells. The morphological and immunohistochemical features pointed towards the diagnosis of TRAPP. We report this rare entity, only 17 cases of which have been described so far in literature. The differential diagnoses have also been discussed.