Clinicopathological, immunohistochemical, and ultrastructural study of 13 cases of melanotic schwannoma / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Melanotic schwannoma is a rare variant of schwannoma composed of melanin-producing cells with ultrastructural features of schwann cells. The description of the course of the tumors differs somewhat, but it is generally considered as a benign lesion. We investigated the clinicopathologic features, immunophenotypes, and ultrastructural features of 13 patients with nonpsammomatous melanotic schwannoma (NPMS).</p><p><b>METHODS</b>Tumor specimens of each patient were sectioned and stained with hematoxylin-eosin, Fontana-Masson, Prussian blue, and periodic acid-Schiff (PAS). Immunohistochemical markers such as S-100, Leu-7, HMB-45, Melan-A, CK, EMA, vimentin, GFAP, laminin, collagen IV and MIB-1 were detected with the Envision immunohistochemical staining method. Four of the cases were observed by electron microscopy.</p><p><b>RESULTS</b>Of the 13 patients, 8 were male and 5 female, aged from 11 to 92 years (mean, 38.6 years). The tumor sites included the spinal nerve root (5 patients), cranial nerve (1), greater omentum (1), subcutaneous tissue (3), mesentery (1), bone (1) and mediastinum (1). Eleven patients were followed up for over 2 years, with a mean of 5.9 years. One patient (9.1%) with a primary tumor in the greater omentum developed another primary tumor of the same type in the subcutaneous tissue of the abdominal wall after the first operation. Local recurrence of the tumor was seen in 2 patients (18.2%). One patient (9.1%) showed the local recurrence and metastasis. Seven patients (63.6%) showed no evidence of the recurrence or metastasis. Grossly, all tumors were well-circumscribed and the gross findings were suggestive of melanin-containing tumors. The tumor was composed of spindled and epithelioid cells with abundant intracytoplasmic melanin pigments. Nuclei were round and contained delicate, evenly distributed chromatins as well as small, distinct nucleoli. In some areas, the nucleoli were large and prominent. Rare mitoses were seen in most lesions except the larger omentum lesion. The pigment was shown to be positive for the Fontana-Masson and negative for Prussian blue and PAS. Immunohistochemical staining for S-100, Leu-7, HMB-45, Melan-A, and vimentin were strongly positive. Linear immunoreactions of both laminin and collagen IV was detected in all patients. Ultrastructurally, numerous elongated tumor-cell processes, duplicated basement membrane and melanosomes were observed in all developmental stages.</p><p><b>CONCLUSIONS</b>Histologically, melanotic schwannoma is a rare variant of schwannoma composed of melanin-producing cells with ultrastructural features of schwann cells. Distinguishing between this tumor and malignant melanoma is of paramount importance in planning of management. Immunohistochemically, combined use of laminin and collagen IV is valuable in distinguishing melanotic schwannoma from malignant melanoma. Wide local resection and additional radiotherapy should be advocated. Further studies including cytogenetic or molecular biology are still required to better delineate melanotic schwannoma from malignant melanoma. Appropriate long-term follow-up is needed for all melanotic schwannomas.</p>

Diagnostic value of A103 and inhibin-alpha in adrenocortical tumors: an immunohistochemical study using tissue microarray techniques / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the potential diagnostic value of A103 and inhibin-alpha in adrenocortical tumors and to evaluate the applicability of tissue microarray/tissue chip in pathological studies using immunohistochemistry.</p><p><b>METHODS</b>A tissue microarray/tissue chip was constructed to contain 179 formalin-fixed, paraffin-embedded adrenal tissue samples which include 3 normal adrenal cortex, 2 fetal adrenal cortex, 2 nodular adrenocortical hyperplasia samples, 72 adrenocortical adenomas, 39 adrenocortical carcinomas, 3 adrenal medulla, 13 metastatic carcinomas, 4 metastatic malignant melanomas and 44 pheochromocytomas. Additional 20 cases of normal adult adrenal gland were used as controls. Immunohistochemical markers, including A103, inhibin-alpha, calretinin and Ki-67 were used on the tissue array sections by EnVision immunohistochemical staining methods.</p><p><b>RESULTS</b>Positive staining of A103 was seen in all of the 23 (100%) adrenal cortex, 2 fetal adrenal cortex, 2 nodular adrenocortical hyperplasia samples, 60 of 66 (90.9%) adrenocortical adenomas samples, 35 of 37 (94.6%) adrenocortical carcinomas samples, 3 of 3 malignant melanomas, but in none of the adrenal medulla, pheochromocytomas or adrenal metastatic carcinoma samples. In all of the adrenal cortex, fetal adrenal cortex and nodular adrenocortical hyperplasia cases, inhibin-alpha immunoreactivity was limited to the zona reticularis and the innermost zona fasciculata. Fifty of the 66 (75.8%) adrenocortical adenomas, 28 of the 37 (75.7%) adrenocortical carcinomas were positive for inhibin-alpha. None of the adrenal medulla, pheochromocytoma, metastatic malignant melanoma or carcinoma samples showed a positive inhibin-alpha immunostain.</p><p><b>CONCLUSIONS</b>The tissue microarray/tissue chip technique provides a reliable method to investigate marker expression by offering a rapid, economic and accurate screening of tissue specimens on a large scale. The combined use of A103 and inhibin-alpha is valuable in distinguishing adrenocortical tumor from pheochromocytoma and other metastatic neoplasms.</p>