Presenter: Zaina Rashid DO
Dermatology Program: Midwestern University/ Arizona Desert Dermatology
Program Director: Don Anderson DO
Submitted on: December 28, 2010
CHIEF COMPLAINT: Brown patch in both armpits for three months
CLINICAL HISTORY: A 73-year-old man presented with asymptomatic dark brown patches in the axillary area for 3 months duration. No previous treatment. There was no history of prolonged sun exposure or trauma in that area. The patient denied any symptoms of pain or pruritus. The patient past medical history includes hypertension with atenolol being his only medication.
PHYSICAL EXAM:
On physical exam, there were well-demarcated brown mottled patches in both axillae. There was no involvement of the extremities, nail, or oral mucosa.
LABORATORY TESTS:
Autoantibodies and complete blood workup were performed resulting in negative or within normal limits outcome.
DERMATOHISTOPATHOLOGY:
Several biopsies were performed showing focal atrophy in the epidermis, a band-like lymphocytic infiltrate associated with pigmented macrophages and interface vacuolar change. A PAS stain was negative for fungal elements, and immunoperoxidase staining for mycosis fungoides was negative as well.
DIFFERENTIAL DIAGNOSIS:
1. Acanthosis nigricans
2. Erythema dyschromicum perstans
3. Mycosis fungoides
4. Axillary granular parakeratosis
5. Lichen planus
