Congenital myofibroma of the skin mimicking a piloleiomyoma.

Myofibroma is an uncommon benign soft tissue disorder, which is usually congenital or present in early infancy. Myofibroma usually manifests as a single mass. When there are multiple lesions, the term myofibromatosis is used. The characteristic histopathological feature of the myofibroma is the coexistence of two distinct areas. One area mainly contains plump spindle cells with thin blunt-ended nuclei and eosinophilic cytoplasm, thus indicating myoid characteristics. The other area contains either round or polygonal cells with slightly pleomorphic, hyperchromatic nuclei or small spindle cells typically arranged around a distinct hemangiopericytoma-like vascular pattern. In the present case, the majority of the tumor was composed of the plump myoid spindle cells. This led to an initial diagnosis of a piloleiomyoma. However, the tumor cells were not immunohistochemically positive for desmin. Moreover, careful examination revealed a hemangiopericytoma-like vascular pattern characterized by the presence of high cellular areas with irregular vascular spaces. These features led to the final diagnosis of the myofibroma. It is therefore important to recognize the leiomyoma-like variants of myofibromas.

Necrotizing fasciitis and myonecrosis "synergistic necrotizing cellulitis" caused by Bacillus cereus.

Our patient was a 37-year-old man with diabetes mellitus and hepatopathy as underlying diseases. Swelling, erythema and pain appeared in the left upper limb on the day before the initial examination. On examination, diffuse purpura was noted on the left upper limb, and, as it rapidly extended to the left upper trunk, emergency surgery was performed. Intraoperatively, gas-producing necrosis was observed not only in subcutaneous tissues but also from the fascia to muscle tissues, and the condition resembled clostridial gas gangrene. However, as the culturing of samples from the lesion yielded Bacillus cereus, a diagnosis of necrotizing fasciitis and myonecrosis (synergistic necrotizing cellulitis) due to B. cereus was made. While the patient developed a serious condition due to sepsis and disseminated intravascular coagulation, he could be saved by early debridement and intensive treatment with an appropriate selection of antibiotics.