Pituitary adenoma with neuronal choristoma: a report of two rare cases

Anterior Gray Matter Pituicytic Heterotopia with Monomorphic Anterior Pituitary Cells: A Variant of Nonsecretory Pituitary Adenoma Neuronal Choristoma? Report of a Rare Case and Review of the Literature

BACKGROUND

Mixed tumors of adenomatous and neuronal cells in the sellar region are an uncommon finding. The origins of these heterogeneous tumors are unknown, and management remains unsettled. We report a very rare case of anterior gray matter pituicytic heterotopia with monomorphic anterior pituitary cells that likely represents a variant of nonsecreting pituitary adenoma neuronal choristoma (PANCH) with no ganglion cells. We also review the current literature for the various clinical presentations of PANCH.

CASE DESCRIPTION

A 49-year-old female complaining of headache, blurred vision, and hair loss was found to have a nonsecretory sellar mass with compression of the optic chiasm on magnetic resonance imaging (MRI). The mass was excised via a transsphenoidal procedure. Histological analysis of tissue sections revealed heterotopic gray matter with reactive gliosis without ganglion cells or Herring bodies. Only 1 smear exhibited characteristics of a pituitary adenoma.

CONCLUSIONS

The overall findings were most consistent with a variant of PANCH. At a postoperative follow-up of 4.5 years, there was resolution of visual symptoms, and the residual sellar mass was stable on MRI. Neuronal choristoma is hypothesized to originate from embryonal pituitary or hypothalamus, or by differentiation from pituitary adenoma cells. Surgery is the cornerstone of management, and the clinical course appears to be similar to that of nonfunctioning pituitary adenoma in reported cases.

Characteristics of ganglion cells in pituitary gangliocytomas

The occurrence of ganglion cells in the sella turcica, in association or not with a pituitary adenoma, has been rarely reported. Various names have been employed for this rare entity, gangliocytoma being frequently used and recommended by WHO classification. Expression of cytokeratin in these ganglion cells has been previously occasionally reported, a very intriguing observation raising questions on the possible nature and derivation of these cells. We describe the pathological findings in three cases of growth hormone-producing adenomas, all sparsely granulated, showing the presence of a ganglion cell population admixed with an adenomatous component. A review of the literature is also provided.

Pituitary adenoma with gangliocytic component: report of 5 cases with focus on immunoprofile of gangliocytic component

INTRODUCTION

Pituitary adenomas with gangliocytic component are rare tumors of the sellar region that are composed of pituitary adenoma cells and a ganglion cell component. Their histogenesis and hence nosology is not yet resolved because of the small number of cases reported and lack of large series in the literature.

METHODS

Herein we report five cases of pituitary adenoma with gangliocytic component to add knowledge to this rare neoplasm.

RESULTS

Three cases are functional mammosomatotroph adenomas, one case is functional sparsely granulated somatotroph adenoma and the other is functional corticotroph adenoma. Gangliocytic component showed immunohistochemical expression of hormones in three cases. The ganglion cells were prolactin immunoreactive in case 1, GH and TSH immunoreactive in case 5 and showed expression of prolactin, TSH, ACTH and FSH in case 4. Three cases had undergone more than one surgery of which two had gangliocytic cells only in the recurrent tumors whereas the third case showed gangliocytic cells only in the initial tumor.

DISCUSSION

The cases are discussed with clinical and histological features and a brief review of the literature considering the histogenesis is included.

Neuronal differentiation and expression of neural epitopes in pituitary adenomas

Neural transdifferentiation is increasingly recognized in neural crest and neural stem cell tumors. Neuronal differentiation has been anecdotally described primarily in somatotroph cell adenomas associated with acromegaly, but its prevalence in adenomas and relationship to adenoma type has not been completely established. In this study we performed a retrospective morphological and immunohistochemical analysis of neurofilament, phosphoneurofilament, Neu-N, class III tubulin, and Hu in WHO grade I pituitary adenomas. Limited numbers of cells with neuronal features and neuron-associated epitopes may be more common in pituitary adenomas than previously recognized. These may occur in many forms of adenomas including somatotroph, lactotroph, mixed somatotroph and lactotroph, null cell/gonadotroph cell and, rarely, corticotroph cell adenomas.

Combined sellar fibrosarcoma and prolactinoma with neuronal metaplasia: report of a case unassociated with radiotherapy

We report the occurrence of a primary pituitary fibrosarcoma causally unrelated to radiotherapy, admixed in association with a prolactin cell pituitary adenoma showing neuronal metaplasia. These unique findings were associated with multiple endocrine neoplasia type 1 (MEN 1). Primary fibrosarcoma involving the sella is a very rare tumor. The majority of cases have been associated with prior irradiation of either a pituitary adenoma or a craniopharyngioma. Pituitary adenoma with neuronal metaplasia is also rare and usually occurs in the setting of acromegaly. Despite the intimate association of both elements in our lesion, no transition of adenoma to sarcoma was demonstrable by immunohistochemistry or in situ hybridization studies.