Abstract

Piezogenic papules are commonly observed in athletes and obese individuals and are associated with underlying connective tissue diseases, such as Ehlers-Danlos syndrome (EDS), and excessive weight-bearing exercise. Typically manifested around the bilateral posterior and lateral borders of the plantar foot and ankles when standing or walking, and on the wrists upon flexion, these soft, smooth, skin-colored to yellow papules are thought to arise secondary to elevated pressure driving herniation of subcutaneous fat into the dermis. Though benign, mechanically-enhanced, and often detected incidentally, associated pain has been reported. Here, we describe a case of a 41-year-old female with hypermobile EDS and a COL5A1 gene mutation who presented with painful subcutaneous papules elicited by rubbing on the bilateral anterior shoulders. After mechanical abrasion of the right infraclavicular fossa, a punch biopsy of one of the papules was performed and revealed lobules of mature adipose tissue impinging into the deep dermis. A Verhoeff stain highlighted patchy diminution and irregular distribution of elastin fibers within the adjacent deep dermal collagen, with foci where this abnormal extracellular matrix was intimately juxtaposed between islands of mature fat. Overall, these histologic findings are in keeping with clinical lesions resulting from mechanically-enhanced herniation of adipose tissue into a structurally compromised overlying dermis. This phenomenon is akin to the pathogenesis of piezogenic pedal papules, herein occurring at an uncommon anatomic location.

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