Plexiform Cellular Schwannoma in Infancy and Childhood: A Clinicopathological Study of Seven Cases of an Underrecognized Nerve Sheath Tumor with a Tendency Toward Local Recurrence

Plexiform cellular schwannoma (PCS) is very rare, and it is not completely understood. We present our experience with 7 additional cases of PCS in infancy and childhood to further characterize its distinctive clinicopathological features. There were 5 females and 2 males with a mean age of 28 months (ranging, 2 months to 8 years). The involved sites included the left forearm ( n = 2), sacrococcygeal region ( n = 2), retroperitoneum ( n = 1), thoracic spinal canal and thoracic cavity ( n = 1), and neck ( n = 1). Tumor sizes ranged from 3 to 13 cm in maximum diameter (mean, 7.1 cm). Histologically, all tumors consisted of abundant spindle cells arranged in a multinodular or plexiform growth pattern, possessing elongated, hyperchromatic nuclei and pale eosinophilic cytoplasm with indistinct cell margins. Mitotic figures were easily identified, with a mean count of 4 per 10 consecutive high power fields (HPF). Immunohistochemically, all tumors were strongly and diffusely positive for S100 protein, SOX10 and H3K27me3. The Ki-67 index ranged from 5% to 30% (mean, 15%). Follow-up (available in 6 cases) revealed that 5 patients experienced local recurrence and were treated by re-excision. There was no evidence of recurrence and metastasis in 3 patients, and the other 2 were alive with the disease. In conclusion, PCS is an uncommon nerve sheath tumor predominantly occurring in infants and children, featuring a plexiform or multinodular growth pattern and exhibiting a tendency toward local recurrence. PCS is easily mistaken as malignant peripheral nerve sheath tumor (MPNST) due to its locally aggressive behaviors and worrisome features, including hypercellularity, hyperchromatism and high proliferative activity. Increased awareness of its potential occurrence and greater familiarity with its characteristic features are helpful for both clinicians and pathologists to avoid misdiagnosis and unnecessary overtreatment.

Phrenic nerve schwannoma: an unusual cause of painless neck lump

Schwannoma (neurilemmoma) arising from the cervical phrenic nerve is a relatively rare tumour type. We describe a case of phrenic nerve schwannoma in the head and neck region in a patient who presented with a painless neck swelling. Analysis of aspiration was suggestive of benign nerve sheath tumour. A computed tomography scan was done to confirm the location and entity of the tumour. The patient was treated with complete excision of the tumour including the maternal nerve fibres. He developed right hemidiaphragm palsy postoperatively, which was treated conservatively. Postoperative immunohistochemistry examination established the diagnosis of cellular schwannoma. The case highlights the challenges associated with the diagnosis and management of cervical schwannoma.

Vaginal Schwannoma

Schwannomas of the female genital tract are extremely uncommon. They are usually benign, and simple excision is the adequate treatment. The case of a 57-year-old woman with a cellular schwannoma of the vagina is described, in addition to a summarized literature review of schwannomas in the female genital tract. Complete excision was performed, and the histological report confirmed to be a vaginal schwannoma. Due to its possibility to occur, even if in a very low incidence scenario, schwannomas should not be excluded from the differential diagnosis of a vaginal mass.

Cellular schwannoma of the breast: A case report and review of literature

Schwannoma of breast is a relatively uncommon disease characterized by painless and slow growing. We report a case of a 28-year-old female who present a mass of the right breast. Ultrasonography revealed a well-circumscribed and inhomogeneous hypoechoic mass under the skin of the breast. Then a biopsy and immunohistochemical analysis were performed. The results were suggestive for cellular schwannoma of breast. The tumour was removed successfully and the patient has been followed-up for six months with no evidence of recurrence. Cellular schwannoma is a rare benign neoplasm without metastasis. Distinction cellular schwannoma from other malignant tumours is very important. It is necessary to combine strict criteria on histological, immunohistochemical analysis, biological behavior, image examination and clinical features for the final diagnosis.

Large retroperitoneal schwannoma: a rare cause of chronic back pain

Schwannomas are tumours that arise from Schwann cells of the peripheral nerve sheath and rarely occur in the retroperitoneum. We report a 45-year-old woman who presented with a 2-year history of continuous progressive right-sided lower back and dull flank pain radiating into her posterolateral thigh. Abdominal magnetic resonance imaging showed a homogenous soft-tissue tumour with thick capsular lining, which lay in the right retroperitoneum. The tumour was removed at surgery. A histological examination confirmed the diagnosis of benign encapsulated cellular schwannoma. Complete tumour excision should be regarded as the treatment of choice for benign retroperitoneal schwannomas. Successful treatment of these tumours requires thorough preoperative planning and a multidisciplinary approach.