Superficial angiomyxoma is a benign cutaneous soft-tissue tumor composed of prominent myxoid matrix, thin-walled blood vessels and scattered spindle cells. Although it usually occurs as a solitary lesion, development of multiple lesions may be associated with Carney complex. We report a 16-year-old woman with an enlarging nipple mass of 2 years' duration. Physical examinations revealed a 15×13-mm polypoid tumor on the right nipple. Histopathological examination of the resected specimen disclosed a dermal myxoid lesion composed of scattered vessels, spindle to polygonal shaped stromal cells and cystic structures lined by stratified epithelium. The myxoid area was positive for Alcian blue staining. The clinical and histopathological features were consistent with the diagnosis of superficial angiomyxoma. No other signs of Carney complex were detected by clinical examinations and imaging studies. We reviewed the literature on solitary superficial angiomyxomas without Carney complex published since 1988 and summarized 224 cases. Local recurrences were reported in 21% of the patients, and the mean time to recurrence wan about 5 years after surgery. Because superficial angiomyxoma is considered to be essentially identical to cutaneous myxomas of the Carney complex, a relatively long-time follow-up is needed to check for tumor recurrence and development of signs of Carney complex especially in young patients.

Schwannomas (neurilemomas) are benign encapsulated tumors that originate in nerve sheaths. They are diagnosed easily when they present with typical symptoms such as radiating pain in the skin. However, they do not present with typical symptoms in most cases, so they are difficult to diagnose. Although ultrasonography is helpful for diagnosing certain skin tumors, reports on ultrasonographic characteristics of schwannomas, especially findings of elastography, are limited. We compared pathological findings with ultrasonographic findings, including those obtained from elastography, in 11 patients in order to elucidate ultrasonographic characteristics of schwannomas and evaluate the usefulness of elastography. In ultrasonography, schwannomas displayed well-circumscribed, low-echoic lesions. They were lobulated in several cases. Heterogeneous and mosaic patterns with partial anechoic areas were observed, accompanied by lateral and posterior echo enhancement. Some lesions showed abundant blood flow; a few were pulsatile. Elastography revealed heterogeneous solidity in most cases. Further accumulation of cases is needed to evaluate the significance of ultrasonography, including elastography, and improve the accuracy of diagnosis.

Multisystem inflammatory syndrome in children (MIS-C) is a new entity disease in which children develop severe cardiovascular disease after SARS-Cov-2 infection. MIS-C presents with a clinical manifestation similar to Kawasaki disease. An 11-year-old boy presented with fever, cardiac dysfunction, and erythema of the trunk and extremities following infection with SARS-Cov-2 three weeks before and was diagnosed with MIS-C. Histopathology of the biopsy showed an erythema multiforme-like pattern. The common skin rashes associated with MIS-C are erythematous papules and erythema multiforme. It has been reported that MIS-C with skin rash exhibits less severe systemic symptoms than MIS-C without skin rash. Kawasaki disease is thought to be caused by molecules produced by pathogenic microorganisms that act on blood vessels and innate immune cells, and MIS-C may be caused by the same mechanism.