Scalp Ulcer: Diagnostic Considerations to Workup Ulcerative CTCL

Scalp ulcers have a broad differential, including infection, trauma, and malignancy. Biopsies are a critical initial diagnostic step for such wounds. We present a unique diagnostic course in a 69-year-old-male where multiple biopsies of his scalp ulceration were insufficient to finalize his diagnosis.

The patient had a 10 x 14 cm ulcerated plaque over his left frontal parietal scalp with granulation tissue and heaped up borders with weeping and draining of purulent fluid. Biopsy of the ulcer performed at an outside hospital showed impetiginized, ulcerative dermatitis with a mixed histiocytic inflammatory infiltrate. Two punch biopsies from the edge of the lesion revealed densely inflamed granulation tissue with a mixed proliferation of CD3+ and CD20+ T and B cells.

The patient also mentioned that his recently diagnosed ‘psoriasis’ was worsening. Over the course of several weeks the ulcer continued to grow and progress, so the patient was urged to present to the Emergency Department for further evaluation. In the ED, the consult dermatology team’s examination additionally revealed scattered sharply demarcated plaques on his trunk and extremities which were deeply indurated and not classic for plaque psoriasis. Three punch biopsies were obtained from the scalp ulcer and one shave biopsy from a plaque on his left upper arm. Results from the ED biopsies revealed tumor-stage mycosis fungoides (MF) on the scalp and plaque-stage MF on the right arm.

Dermatopathology noted that the diagnosis would not have been possible without the arm biopsy; although the ulcerated scalp lesion had atypical lymphocytic infiltrates, it lacked distinctive findings and did not have a high proportion of large lymphocytes. This case highlights that scalp ulcers should not be treated in isolation, and that histologic evaluation is needed beyond the ulceration to establish a diagnosis of ulcerated cutaneous T cell lymphoma.