Photo Rounds

Scar overgrowth

A 45-year-old woman with a history of a shoulder fracture presented to Dermatology with a 4 x 3 cm flesh-colored plaque occurring over a previous surgical scar. Dermoscopy demonstrated multiple shiny white lines at right angles on a translucent background. A 4-mm punch biopsy was performed from a central portion of the plaque to assess the full thickness of the skin.

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References

Scar overgrowth

Dermatopathology was consistent with a diagnosis of cutaneous myxoma (CM). There are very few dermoscopic descriptions of CM in the literature, so diagnostic features are not established. However, the absence of more diagnostic features of basal cell carcinoma or squamous cell carcinoma (SCC) increases the likelihood of a rare diagnosis, such as CM.

CMs are rare benign neoplasms that manifest most commonly in young adults as small (< 1 cm) flesh-colored to blue papules on the head, neck, and trunk. The size of this particular CM was an outlier. CMs may be associated with Carney Complex (CNC), a rare inherited syndrome that has been linked to multiple endocrine neoplasias—namely, pituitary adenomas, testicular Sertoli cell tumors, thyroid tumors, and cardiac atrial myxomas.1 Additionally, in CNC, lentigines and multiple blue nevi develop on the skin and mucosal surfaces.

The differential diagnosis for a large, pink to flesh-colored nodule of this size includes benign histiocytoma, SCC, CM, and dermatofibrosarcoma protuberans. Benign histiocytomas and SCCs are much more common than CM. Clinical features only hint at the correct diagnosis, which must be made histologically.

Patients with CMs benefit from ongoing dermatology surveillance to monitor for the development of atypical nevi or new CMs. In this case, a wide excision with generous margins was planned with plastic surgery. (CMs have been reported to recur after surgery, which is why wide margins are essential.)

Additionally, 2 factors prompted an echocardiogram: the association between CMs and possible cardiac tumors and the patient’s need to undergo future orthopedic surgery under general anesthesia. No cardiac tumors were visible on echocardiogram. Thyroid imaging and genetic evaluation were planned but not completed.

Photos and text for Photo Rounds Friday courtesy of Jonathan Karnes, MD (copyright retained). Dr. Karnes is the medical director of MDFMR Dermatology Services, Augusta, ME.

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