Benign glandular peripheral nerve sheath tumor. A case report

Glandular Schwannoma With Apocrine Decapitation Secretion: A True Divergent Differentiation or Entrapped Normal Tissue?

ABSTRACT

We report an unusual case of schwannoma with glandular elements that demonstrated apocrine decapitation secretion. The glandular structures were embedded within the tumor, varied in shape and size, and were lined by a double-to-multilayered epithelium, with the inner layer composed of monomorphous cuboidal to columnar cells, focally with apocrine decapitation secretion, and the outer layer representing myoepithelial cells. A normal eccrine unit was observed near the lesion. Immunohistochemical studies showed that all luminal cells of the glandular structures stained positive for CK7, whereas myoepithelial cells expressed S100 and p63, and epithelial membrane antigen highlighted the luminal border. CK20 and neuroendocrine markers were negative in the glandular elements.Our findings suggest that the origin of the glandular elements in our case was represented by entrapped glands. Two theories may explain the epithelial hyperplasia observed in the present case as follows: the obstructive effect theory and the inductive ability of a mesenchymal proliferation to produce epidermal or adnexal changes. We suggest that, in a subset of cases, the origin of the glandular elements might represent entrapped glands, wherein their histomorphology/cytomorphology recapitulates the elements comprising the normal adjacent tissue. Further research is necessary to elucidate the histogenesis of glandular schwannoma.

Glandular Schwannoma: An Uncommon Variant of Schwannoma with Controversial Histogenesis

Schwannomas are benign, encapsulated nerve sheath tumors arising from Schwann cells; several histologic variants of schwannoma have been described, including the exceedingly rare glandular schwannoma (GS). The histogenesis of the glands in GS (as well as in other peripheral nerve sheath tumors with a glandular component) remains unclear; no consensus exists as to whether glands should be interpreted as metaplastic elements or entrapped reactive glands. We report a case of GS with detailed immunohistochemical analysis of the epithelial component. We believe that our findings raise further questions regarding the histogenesis of glands in GS, casting doubts on the traditional distinction between true metaplasia and glandular entrapment. Further research is warranted in this regard.

Benign Glandular Schwannoma in Basal Ganglia

BACKGROUND

The oncogenesis and biologic behaviors of benign glandular schwannoma have not been clinically unveiled because of its rarity and variability.

CASE DESCRIPTION

However, we report a young male patient who presented with a benign glandular schwannoma in the basal ganglia, a site that has not been reported in any literature. Histologically, the samples are composed of spindle-shaped cells and variable glandular structures. The spindle-shaped cells are identified with the appearance of Antoni A and Antoni B zones. Moreover, the glandular structures are lined by stratified epithelial cells, glandular epithelium cells, intestinal epithelial cells, and few degenerative syncytial macrophage cells. Hemorrhage, necrosis and cystic changes were observed in the specimen cells, but no mitotic figures were found. The immunohistochemical results showed that the spindle cells were stained with S-100 protein, but lacked carcinoembryonic antigen (CEA), cytokeratin pan (AE1/AE3) (CK), synaptophysin, chromogranin A, and glial fibrillary acidic protein reactivity after surgery. Meanwhile, the glandular epithelium cells mostly consisted of glandular epithelium and stratified epithelium cells stained with CEA, chromogranin A, and CK antigen.

CONCLUSIONS

Therefore, the morphologic and immunohistochemical findings support the diagnosis of benign glandular schwannoma.

Microcystic pseudoglandular plexiform cutaneous neurofibroma

Glandular structures are well documented to appear in peripheral nerve sheath tumors. These epithelial elements are usually present in malignant peripheral nerve sheath tumors although a few cases of glandular benign peripheral nerve sheath tumors have also been described, most of them being schwannomas. A neurofibroma with glands is considered to be a rare type of divergent differentiation, but a neurofibroma containing gland-like or pseudoglandular structures have not, to our knowledge, been described. We report a 33-year-old patient with a well-demarcated dermal neoplasm, composed of neoplastic Schwann cells, perineurial-like cells and fibroblasts in a matrix with collagen fibers and myxoid areas. A part of the tumor consisted of microcystic gland-like spaces lined by flat cells. These cells were either S100 positive or negative, with no epithelial membrane antigen, cytokeratin or CD31 immunostaining. Recognition of the presence of pseudoglandular elements in neurofibromas is important to distinguish them from other tumoral lesions, some of them with malignant potential.

Unusual histological presentation in neurofibromas: Two case reports

Various histological variants of neurofibroma have been described. The objective of this paper is to discuss the unusual histological findings seen in two cases of neurofibromas associated with neurofibromatosis type 1 Both cases presented with multiple subcutaneous nodules. Surgical excision of the largest nodule was done in both the cases. Histological examination of case no.1 revealed a benign tumor of the peripheral nerve sheath, of neurofibroma type with presence of mucus producing glands. The epithelial component was benign in this case. The second case showed presence of rosettes in between areas of typical neurofibroma.

An unusual case of glandular schwannoma

Glandular differentiation is exceedingly rare in peripheral nerve sheath tumors. In this report, an exceptional case of retroperitoneal glandular schwannoma is described in which the glandular element is markedly atypical, whereas the schwannian component is benign by morphologic analysis. To the best of our knowledge, the biologic behavior for such a lesion is unknown because similar cases have not yet been described in the literature.

Malignant peripheral nerve sheath tumor with divergent mesenchymal differentiations in a dog

A malignant peripheral nerve sheath tumor with divergent osteogenic, myxomatous, and myoblastic differentiations is described in a 10.5-year-old male Labrador Retriever dog. The tumor involved the sixth and seventh cervical spinal cord segments and nerves. The diagnosis was based on the results of histopathology, electron microscopy, and immunohistochemistry.

Non-neoplastic glandular structures in a benign peripheral nerve sheath tumor

It is a recognized fact that glandular structures sometimes occur in peripheral nerve sheath tumors (PNST). Reports indicate that epithelial potential could be expressed in malignant PNST, while the glands in most benign PNST could be trapped skin adnexa. We present a case of spindle cell tumor with glandular structures. The patient was a 55-year-old man who had a subcutaneous tumor excised. The spindle cell tumor had histological characteristics of neurofibroma. The glandular structures had a pattern of immunohistochemical staining that was similar to that of the secretory coils and excretory ducts of normal eccrine glands. Therefore, the glands were thought to be naturally existing eccrine glands. The glands were completely enclosed within the tumor and not connected to one another; a cluster formation was not observed. The upper portion of tumor included some glands of skin adnexa. The spindle cell tumor may have originated from the nerves distributed around the skin adnexa, and grown to the subcutaneous tissue. The glands may have been left behind rather than have been trapped in the tumor.