Angioplasmocellular hyperplasia: A clinicopathologic study of 10 patients

Expression of Peripheral Node Addressins by Plasmacytic Plaque of Children, APACHE, TRAPP, and Primary Cutaneous Angioplasmacellular Hyperplasia

High-endothelial venules are a common feature of 3 types of cutaneous pseudolymphomas: pretibial lymphoplasmacytic plaque (PLP) of children, acral pseudolymphomatous angiokeratoma of children (APACHE), and T-cell rich angiomatoid polypoid pseudolymphoma (TRAPP). In addition, primary cutaneous angioplasmacellular hyperplasia (PCAH) overlaps with these other 3 conditions. We intend to study the expression of peripheral node addressins in PLP, APACHE, TRAPP, and PCAH. We studied 1 case of PLP, 2 cases of APACHE, 2 cases of TRAPP, and 2 cases of PCAH. Immunostainings for MECA-79 and WT-1 were obtained in all cases. All cases showed a dense lymphohistiocytic dermal inflammatory infiltrate with abundant plasma cells. In addition, HEV were prominent in all cases. Cases of PLP, APACHE, and TRAPP expressed MECA-1. Cases of PCAH did not express MECA-1. Although PLP, APACHE, and TRAPP seem to fall under the same morphologic spectrum with different clinical representations, PCAH seems to be a different entity, with histopathologic peculiarities and a different immunophenotype.

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.