Superficial malignant schwannoma on the face: a case for early radical surgery

Cutaneous epithelioid malignant peripheral nerve sheath tumour: a clinicopathological analysis of 11 cases

AIMS

Epithelioid malignant peripheral nerve sheath tumour (E-MPNST) is a distinctive variant of malignant peripheral nerve sheath tumour characterized by the predominance of epithelioid cells, diffuse S100 positivity and infrequent association with neurofibromatosis type 1. The aim of this study was to further delineate clinicopathological features of cutaneous E-MPNST, correlate them with disease outcome and discuss differential diagnosis.

METHODS AND RESULTS

We analysed 11 cutaneous E-MPNSTs (six males, five females, median age 49 years, median size 1.6 cm). Tumours showed a predilection for lower extremities (45%) and trunk (45%), followed by upper extremity (9%). Follow-up was available for nine of 11 patients (range 24-100 months, median 52 months). Four patients had an uneventful clinical course (44%), two developed local recurrence(s) (22%) and three died due to disseminated disease (33%). No histological parameters were found to predict local recurrence(s), development of distant metastases or disease outcome, including size, percentage of epithelioid component, number of mitoses per 10 high-power fields, degree of nuclear atypia or site of occurrence (dermis, dermis/subcutis, subcutis) (P > 0.05). Immunohistochemically, all tumours were diffusely S100-positive, with a subset displaying loss of integrase interactor 1 (INI1) expression (50%).

CONCLUSIONS

Cutaneous E-MPNST has the potential to pursue an aggressive clinical course, associated with wide dissemination and unfavourable disease outcome.

Malignant peripheral nerve sheath tumors of the lateral skull base

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive spindle cell tumors that develop from peripheral nerve sheath cells and account for 5% of all soft tissue sarcomas. MPNSTs involving the lateral skull base are an extremely rare subgroup of these lesions. The article deals with the case of a 51-year-old man with a huge primary MPNST: the disease involved the left frontozygomatic and retroauricolar regions of the scalp with erosion of the outer table of the calvaria and diffuse infiltration of the temporal, infratemporal, and pterygoid fossae. Radical surgery via left transfacial- transparotid approach and reconstruction with microvascular flap were performed. Intraoperative radiotherapy and postoperative radiotherapy were also delivered. Twenty-two months postoperatively, the patient is alive despite recurrence of the tumor in the neck and lung metastases. The article reviews the few series of patients and the small number of case reports of MPNSTs involving the lateral skull base that are available in the English literature describing current concept of pathophysiology, diagnosis, and management of the disease. Although MPNSTs of the lateral skull base have an adverse prognosis, an acceptable survival time and a good quality of life are possible; however, they require an early and correct diagnosis as well as an adequate and aggressive combination therapy.

Epithelioid Malignant Peripheral Nerve Sheath Tumor in the Infraorbital Nerve

Epithelioid malignant peripheral nerve sheath tumors are rarely found in cranial nerves. This report describes one such tumor originating from the infraorbital nerve in a 55-year-old man who presented with diplopia and right cheek numbness. Imaging showed a mass along the floor of the right orbit, which was excised. Histology suggested melanoma or carcinoma. Immunohistochemical staining was positive for S-100 and negative for HMB-45 and cytokeratin. Four other cases from the literature involving cranial nerves are discussed.

Superficial malignant schwannoma of the scalp

BACKGROUND

Malignant schwannoma is a rare sarcoma that is located mostly on trunk and extremities; the head and neck are unusual sites for its development. Almost half of these tumors arise from neurofibromas with or without von Recklinghousen's disease, and most of the remainder develop de novo from peripheral nerve trunks. Development in the superficial soft tissues is extremely rare.

OBJECTIVE

To present a case of superficial malignant schwannoma of the scalp, which is an uncommon presentation.

METHODS

An 80-year-old male patient presented with a painless ulceration on his scalp. The clinical and radiologic properties of the tumor were consistent with a skin tumor.

RESULTS

The lesion was excised, and reconstruction was achieved by transposition scalp flap. Malignant schwannoma was given as diagnosis by histopathologic examination with immunohistochemistry.

CONCLUSION

Malignant schwannomas may also occur in the skin. Clinically, these superficial forms closely resemble skin tumors, especially malignant melanoma. The treatment of choice in these tumors is wide resection combined with radiotherapy.

Desmoplastic neurotropic melanoma. A clinicopathologic analysis of 28 cases

BACKGROUND

Desmoplastic neurotropic melanoma (DNM) is a rare variant of malignant melanoma, the natural history and histogenesis of which still are being defined.

METHODS

The clinical and histologic features of 28 cases of DNM were studied. All published cases of DNM to date were reviewed. Paraffin sections from 26 cases were investigated with a panel of 10 tissue markers. The ultrastructural features of seven cases were evaluated.

RESULTS

A comparison of this study's findings with that of other published cases revealed many similarities regarding clinical and pathologic findings and outcome. The patients were white (15 men:13 women; mean and median age, 59 years; range, 22-83 years). Most tumors were located on the head and neck (75%) and were nonpigmented (57%). An associated intraepidermal melanocytic proliferation was identified in 85% of the patients (lentigo maligna in 56%). Histologically, the dermal tumors were composed of tapered, nonpigmented spindle cells in peripheral nerve sheath patterns resembling neuromas, schwannomas, neurofibromas, and perineurial proliferations accompanied by variable neurotropism and desmoplasia; desmoplasia was the most notable feature in most tumors. The mean depth of tumor invasion was 4.1 mm (range, 0.32-9.0 mm). Tumors with continuity between the epidermal and dermal components had a significantly thinner depth of invasion and a more extensive intraepidermal melanocytic proliferation than those tumors with a grenz zone between the two components (2.3 mm vs. 4.6 mm, P = 0.015). Mitotic activity ranged from 0/HPF in 10 cases, 1-6/high power field (HPF) in 12 cases, and to greater than 6/HPF in 4 cases. An ulcer was present in 5/27 tumors, regression in 4/27, a microsatellite in 1, and brisk and had nonbrisk tumor infiltrating lymphocytic responses in 2 and 14, respectively. Vimentin was uniformly positive and keratins AE1.3 and Cam 5.2 and Leu-7 were uniformly negative. S100 protein, also uniformly positive, had patchy reactivity in most tumors that expressed EMA (43%). Smooth muscle actin (52%), neuron-specific enolase (42%), and FXIIIa (30%) had patchy positivity. HMB-45 was reactive only in the epidermal and superficial papillary dermal component in 21% of cases. Ultrastructurally, the common features were long, often intertwining cellular processes, intercellular junctions, and discontinuous basal lamina. Melanosomes were not identified. Follow-up data available on 26/28 patients (mean, 36 months; median, 24 months; range, 5-132 months) showed 20 (70%) alive without disease, 2 alive with disease and 3 dead from disease. Seven patients had recurrent local tumor (multiple in four); four had lymph node metastases, and three had visceral metastases. Patients with recurrent disease of any type had significantly thicker tumors (5.4 mm vs. 3.4 mm, P = 0.046) and were more likely to have an ulcerated tumor (P = 0.03). Actuarial 5-year survival for tumors with greater than a 4-mm thickness was 72%, which was greater than that for other types of melanoma with greater than a 4-mm thickness.

CONCLUSIONS

Desmoplastic neurotropic melanomas are neuroectodermal tumors that usually arise from an intraepidermal melanocytic proliferation but rarely develop de novo in the dermis. Schwannian and perineurial differentiation may account for the desmoplasia and neurotropism encountered in these neoplasms. Desmoplastic neurotropic melanomas present at a more advanced stage locally and may be associated with a better survival than associated with conventional melanomas of similar depth of invasion.

Superficial epithelioid schwannoma presenting as a subcutaneous upper eyelid mass

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