A 35-year-old woman sought care at our clinic for a plaque on her upper left arm. She said that it had started 3 months earlier as a small indentation, but had recently became larger and hyperpigmented. The lesion was not pruritic or painful, and she had no associated weakness or systemic symptoms. The patient denied any insect bites, instrumentation, topical ointments, or trauma to the area.
Physical examination revealed a 3.5 × 2.5 cm area of hyperpigmentation on the posterior aspect of the left arm, overlying the musculotendinous junction of the lateral head of the triceps (FIGURE 1). The lesion had an irregular border and a central region approximately 1 cm in diameter associated with a nontender subcutaneous mass that felt tethered to the skin. There was significant thinning of the subcutaneous fat beneath the hyperpigmentation relative to the normal surrounding skin. The patient had normal triceps function and a normal distal neurovascular exam.
Concerned about malignancy, we ordered computed tomography (CT) and magnetic resonance imaging (MRI) of the left arm. Both demonstrated a nonspecific density in the subcutaneous tissue, and focal indentation and architectural distortion of the skin and subcutaneous tissue in the area in question. In addition, the MRI showed skin tethering extending to the superficial myofascial layer of the posterior triceps muscle and a small superficial blood vessel (FIGURE 2).
We referred the patient to Plastic Surgery for tissue diagnosis. A punch biopsy revealed dense dermal sclerosis that could be consistent with a morphea-like process. As malignancy could not be excluded, the patient was then referred to a dermatologist to determine the need for excision.
A 3.5 × 2.5 cm lesion on the left posterior arm
MRI reveals skin tethering to superficial myofascial layer
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