Photo Rounds

Black lesion on arm

A 51-year-old woman went to see her family physician (FP) about the rapidly growing black lesion that had developed on her left upper arm. She wasn’t sure when the lesion had first appeared, but she noticed that it had been growing fast for the past 2 months. A month earlier, it had become painful and the skin around it had turned red. She sought care for it when she was able to get health insurance.

What’s your diagnosis?


Black lesion on arm

Due to the dark and rapidly growing nodule, the FP immediately worried about melanoma.

He thought that he should biopsy the entire lesion with an elliptical excision, so he scheduled the patient for a biopsy during some protected surgical time later that week. The patient did not show up for this appointment. Several calls were placed, and she returned for the biopsy the following week. The FP performed a narrow margin (2 mm) elliptical excision oriented to match the lymphatic drainage of the arm. He closed the excision with a 2-layer closure. (See the Watch & Learn video on elliptical excision.) The pathology report confirmed that it was a nodular melanoma that was 8 mm in depth. This was clearly an aggressive tumor, so the patient was referred to Surgical Oncology for sentinel lymph node biopsy. One node was positive for metastasis.

After a wide excision with 2 cm margins by Surgical Oncology, the patient underwent a course of chemotherapy and remained disease free 2 years later. She was carefully monitored for metastasis and new primary lesions by a multidisciplinary team that included family medicine, dermatology, and oncology.

While this FP handled the case in an excellent matter, he was fortunate to have the skills and time to be able to perform a full elliptical excision. It’s important to note that a 6 mm punch biopsy or a deep shave biopsy (saucerization) at the base of the thickest portion of this tumor would almost certainly have provided the same diagnosis of melanoma and at least showed that the tumor was thicker than 4 mm (an important cut-off for management). This could have been done on the day of original presentation and might have avoided the problem of the patient not showing up for the next appointment or a long delay to see a dermatologist.

FPs should be empowered to perform biopsies on the most worrisome of lesions as these biopsies can save lives. While incomplete sampling can result in false negative results and misdiagnosis, the protection against this is to not accept a benign pathology report in what appears to be an obvious malignancy. If this occurs, the next step is always complete excision. Having options and understanding potential sampling errors can help FPs diagnose patients more rapidly. This is essential when cancers are rapidly growing and delays of months for surgical appointments or referrals to specialists can worsen a prognosis.

Photos and text for Photo Rounds Friday courtesy of Richard P. Usatine, MD. This case was adapted from: Karnes J, Usatine R. Melanoma. In: Usatine R, Smith M, Mayeaux EJ, et al. Color Atlas and Synopsis of Family Medicine. 3rd ed. New York, NY: McGraw-Hill; 2019:1112-1123.

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