Pituitary carcinoma diagnosed on fine needle aspiration: Report of a case and review of pathogenesis

Abstract

Pituitary carcinoma (PC) is a very rare entity (0.2% of all pituitary tumors), with only about 140 cases reported in English literature. There are no reliable histological, immunohistochemical or ultrastructural features distinguishing pituitary adenoma (PA) from PC. By definition, a diagnosis of PC is made after a patient with PA develops non-contiguous central nervous system (CNS) or systemic metastases. To date, only three cases of PC have been reportedly diagnosed on fine needle aspiration (FNA). Two of the reported cases were diagnosed on FNA of the cervical lymph nodes and one on FNA of the vertebral bone lesion. Herein, we present a case of PC, diagnosed on FNA of the liver lesion. In this case, we describe cytologic features of PC and compare them to histologic features of the tumor in the pituitary. Clinical behavior of tumor, pathogenesis of metastasis and immunochemical and prognostic markers will also be described.

Cytomorphology of metastatic pituitary carcinoma to the bone

“…The FNA cytomorphology of metastatic pituitary carcinoma reported in the literature can show a combination of loose groups, microacini, and single cells, as well as uniform bland or mildly pleomorphic plasmacytoid cells displaying characteristic neuroendocrine tumor features (round to oval eccentrically placed nuclei with coarsely granular chromatin and small nucleoli, and moderate fragile cytoplasm) . These reported cytologic features of metastatic pituitary carcinoma were seen in our case.…”

Cytomorphology of pituitary carcinoma metastatic to liver diagnosed by fine-needle aspiration: A rare case report and review of literature

“…However, the reason of frequent liver metastasis still remains unclear. [ 6 ] The interval between PA and metastasis development is highly variable ranging between 4 months and 30 years; however, in the present case, metastasis developed within 6 weeks of the detection of primary tumor.…”

What is your diagnosis? Pituitary mass in a dog

“…Adenomas can be further classified as macroadenomas when greater than 1 cm in diameter . Invasive adenomas are characterized by local infiltration, a higher proliferation rate, and increased vascularity . In people, there are no reliable histologic, immunohistochemical, or ultrastructural features that define a pituitary adenocarcinoma other than metastasis .…”

“…Macroadenomas are estimated to occur in 10–50% of pituitary‐dependent hyperadrenocortism cases, but potentially occur in as many as 75% of the reported cases . Adenocarcinomas are less common, occurring at an estimated rate of approximately 6%, and are thought to arise from malignant transformation of preexisting adenomas, especially invasive macroadenomas . In the dexamethasone suppression and ACTH stimulation test, there is no difference between adenoma and macroadenoma, although ACTH precursor levels appear to correlate with pituitary gland size…”

“…Cytologically, anterior pituitary tumors exhibit a neuroendocrine pattern composed of medium‐sized cells with eccentric, round to oval or mildly pleomorphic nuclei with stippled chromatin and small nucleoli, and in people, intracytoplasmic hyaline material may accumulate . Carcinomas may consist of a pleomorphic or a homogenous cell population, and functional tumors are more likely to exhibit nuclear pleomorphism and have a higher mitotic index…”