A Rare Case of a T-Cell Rich Angiomatoid Polypoid Pseudolymphoma in a 31-Year-Old Pregnant Woman.

T-cell rich angiomatoid polypoid pseudolymphoma (TRAPP) is a rare skin condition with important clinical and histological differentials. We report a case arising on the left cheek of a 31-year-old pregnant female, first noticed at 7 months of pregnancy. By the time of excision soon after delivery, it was 6 mm in diameter. Histology showed a relatively circumscribed dermal proliferation of high endothelial venule-like vessels, surrounded and densely infiltrated by non-atypical CD4 positive T lymphocytes. A diagnosis of TRAPP was made. To our knowledge this is only the second case in the literature to arise during pregnancy. We review the literature on TRAPP, discuss its histological and immunohistochemical features, recently proposed changes to its nomenclature, and distinguishing features that separate it from its main differential diagnoses.