Acquired reactive perforating collagenosis associated with papillary thyroid carcinoma: a paraneoplastic phenomenon?

Acquired reactive perforating collagenosis (ARPC) is an uncommon dermatosis characterized by transepidermal elimination of altered collagen. It is commonly seen in patients with diabetes mellitus and/or chronic renal insufficiency. Rarely, it has been reported in association with malignancy and other conditions. We report a 30-year-old woman with insulin-dependent diabetes mellitus who presented with multiple, discrete, violaceous, hyperkeratotic papules on the extensor aspects of both legs, characteristic of ARPC. Four months later, metastatic papillary thyroid cancer was diagnosed. This case further supports the possibility that ARPC may represent a paraneoplastic phenomenon.