A 51-year-old woman is referred to dermatology for multiple problems she has had for several months—and, in some cases, years. The most immediate is a new nodule on the side of one thumb. Although it is asymptomatic, the fact that it simply “appeared” worries her, because her favorite uncle recently died of melanoma.
Several new lesions also materialized on her finger pads and chest. These do not cause symptoms either, but their newness makes them worrisome.
When asked about her health in general, the patient initially states it is “fine”—until her husband corrects her. She then recalls that she is being seen by various specialists, including a gastroenterologist for dysphagia-like symptoms and a rheumatologist for vague joint pains and what sounds like Raynaud disease.
EXAMINATION
On the lateral right thumb is a shallow, intradermal, white lesion. It is firm and round and measures 5 mm. No overlying skin changes (eg, redness or disruption of the skin surface) are observed. Under local anesthesia, a small incision is made in the lesion’s surface, allowing for exploration with small forceps; granular, gritty, white material is extracted.
On the affected thumb and two other fingers, telangiectasias can be seen. There are additional patches on the patient’s chest, but none around her mouth.
No sign of Raynaud disease is seen. However, the patient is adamant that this only appears when her hands are quite cold.
What is the diagnosis?