Perianal fetal rhabdomyoma: case report

Upper Esophageal Fetal Rhabdomyoma: A Case Series of 4 Children and Review of Literature

Objective: The aims of the present study were to provide objective evidence for identifying fetal rhabdomyoma (RM) in the upper esophagus of children, enhance clinical understanding of the diagnosis and treatment of this condition, and optimize the treatment strategy for fetal RM. Methods: The clinical medical records of 4 children with upper esophageal fetal RM were retrospectively collected, and were admitted to the Department of Otolaryngology, Head and Neck Surgery at our hospital between July 2016 and July 2022. Their clinical, histological, and therapeutic characteristics were analyzed in combination with the literature. Results: Four children diagnosed with upper esophageal tumors were included and all of them underwent resection of the upper esophageal tumor with esophageal-pharyngeal reconstruction, and 2 of them underwent prophylactic tracheotomy due to recurrent laryngeal nerve adhesion. Preoperative biopsy was performed in 2 cases (case 2 and case 4), while intraoperative frozen section analysis was conducted in the other 2 (case 1 and case 3), with pathological results consistent with fetal RM. Patients were followed up for 25 to 96 months after the surgery. So far, only 1 patient has experienced a recurrence of fetal RM and underwent a second surgical resection to remove the tumor. Conclusion: Fetal RM is a benign tumor prone to recurrence, and complete excision is the preferred optimal treatment. Clinicians need to understand and master the management algorithm for fetal RM to standardize its diagnosis and treatment.

Soft Tissue Special Issue: Skeletal Muscle Tumors: A Clinicopathological Review

Skeletal muscle tumors are classified into rhabdomyoma and embryonal, alveolar, spindle cell/sclerosing and pleomorphic rhabdomyosarcoma according to WHO classifications of tumors. These tumors arise mostly in the head and neck and, in childhood, represent the largest subset of soft tissue tumors. Although these skeletal muscle tumors show common immunoexpression of two myogenic regulatory factors, MyoD1 and myogenin, their molecular biological backgrounds are quite different. Therefore, treatment regimens vary a great deal depending on the histological subtype. Histopathologically, rhabdomyoma is characterized by well-demarcated lesions with no invasion of the surrounding tissue. Embryonal rhabdomyosarcoma is composed of primitive mesenchymal cells in various stages of myogenesis and shows heterogeneous nuclear staining for myogenin. Alveolar rhabdomyosarcoma, on the other hand, shows a proliferation of uniform primitive round cells arranged in alveolar patterns. The tumor cells at the periphery of alveolar structures adhere in a single layer to the fibrous septa. Diffuse and strong nuclear immunoexpression for myogenin is observed. In genetic backgrounds, almost all alveolar rhabdomyosarcomas contain a characteristic fusion gene such as PAX3/7-FOXO1. Spindle cell/sclerosing rhabdomyosarcoma is characterized by fascicularly arranged spindle-shaped cells or dense hyalinized collagenous matrix. NCOR2- or VGLL2-related gene fusions or MYOD1 (p.L122R) mutation is commonly recognized. Epithelioid rhabdomyosarcoma is a rare variant of rhabdomyosarcoma that shows a proliferation of epithelioid tumor cells having large vesicular nuclei, prominent nucleoli, and amphophilic to eosinophilic cytoplasm arranged in sheets. As these characteristic histological and molecular features are present in each subtype, it is possible to diagnose skeletal muscle tumors accurately.

"Sclerosing" Pelvic Floor Rhabdomyoma

PURPOSE

This article reports on a sclerosing perineal-perianal rhabdomyoma in an adult woman. A review of the literature disclosed no reference to this histological form of rhabdomyoma in women.

METHODS AND RESULTS

We describe the case of a 48-year-old woman. At physical examination, a firm nodular lesion was identified in the left lateral perianal-perineal region. Histologically, it comprised rounded and elongated muscle fibers displaying no evident atypia, within a stroma exhibiting marked sclerosis and mild lymphoid infiltrate. At immunohistochemical examination, tumor cells stained for desmin, muscle-specific actin, and myogenin.

CONCLUSIONS

Skeletal muscle rhabdomyomas are rare benign tumors, generally divided into 3 major categories depending on their clinical and morphological characteristics: fetal, adult, and genital. An unusual histological variant of the genital form has recently been reported in men, characterized by the presence of predominantly mature muscle fibers and marked sclerosis. We document such a lesion in a female patient for the first time.

Perianal rhabdomyosarcoma presenting 21 months after hamartoma excision

Perianal rhabdomyosarcoma is a rare type of tumor with a relatively poor prognosis. We present the case of a patient who presented with a cutaneous perianal hamartoma at the age of 6 weeks. 21 months latter a recurrent mass at the excision site proved to be an embryonal rhabdomyosarcoma involving the anal sphincter. A pathologic review of the two specimens confirmed their relatedness. This report highlights the need to maintain a high level of suspicion in cases of recurrence following excision of a benign lesion.