The correct answer is to perform a 3-mm punch biopsy (choice “a”).
When the history and physical exam fail to point to a clear diagnosis, skin biopsy can answer a very basic question: What is the pathophysiologic process associated with the lesions? The information thus obtained doesn’t always produce a blinking neon sign of a diagnosis, but at a minimum, it can rule out a great number of things, such as cancer or infection.
More often, the types of cells seen, and the patterns in which they are arranged, tell us a great deal. In this case, accumulations of monocytes, macrophages, and activated T-lymphocytes were arranged in circular patterns, but there was no evidence of necrosis (caseation), which can be seen in tubercular granulomas. Stains performed to identify mycobacterial organisms were negative. These findings established the diagnosis of cutaneous sarcoidosis, a granulomatous disease thought to represent a reaction to an unknown antigen (eg, a microorganism) or environmental substance. It is far more common in those with darker skin types.
Although this patient’s disease was confined to the skin, sarcoidosis can affect virtually any other organ in the body—in particular, the lungs, kidneys, liver, nervous system, or even the eyes. For this reason, patients with sarcoidosis are usually referred to pulmonology for a workup intended to rule out systemic involvement and to other specialists as symptoms dictate.
Many cases of sarcoidosis remit on their own, without treatment. When treatment is initiated, the 2 most commonly used medications are systemic glucocorticoids and/or methotrexate. Both drugs have been associated with serious adverse effects and should only be prescribed by experienced providers.
This combination was prescribed for the case patient, who obtained rapid relief. Blood work (complete blood count, comprehensive metabolic panel) was within normal limits prior to and during treatment, and the pulmonologist pronounced her free of lung involvement.