Calcification in a chromophobe adenoma. Case report

Endoscopic endonasal resection of nonfunctioning pituitary adenoma with radiological calcification

OBJECTIVE

Radiological calcification in nonfunctioning pituitary adenoma is scarcely rare, which appears in various formations and raises special diagnostic and therapeutic challenges. Here we present our experience about the clinical aspects and treatment of calcified nonfunctioning pituitary adenoma.

METHODS

A total of 145 patients who underwent surgical resection of nonfunctioning pituitary adenomas via endoscopic endonasal approach from February 2008 to December 2018 were reviewed. Among these patients, cases with radiological calcifications on preoperative imaging were included in this study. We analyzed these patients' records, radiological neuroimaging, endocrine evaluation, operative notes as well as intraoperative videos.

RESULTS

Calcification on preoperative neuroimaging was observed in only 7 patients with nonfunctioning pituitary adenomas. The study population consisted of these seven patients with intra-tumor calcification (n = 2), thin and egg shelf-like capsular calcification (n = 3), hard and armor-like capsular calcification (n = 2). In 85.7% of cases (n = 6), nonfunctioning pituitary adenomas with calcification were characterized by soft tumor texture. Evidences demonstrated apoplexy occurred in 71.4% of cases with calcified pituitary adenomas (n = 5). Patients with intra-tumor calcification as well as with thin and egg shelf-like capsular calcification underwent resection of both tumor and calcification through extra-pseduocapusual dissection via endoscopic endonasal approach. Besides, in the remaining 2 cases (28.6%), hard and armor-like capsular calcification was found surrounding a soft tumor component; however, it did not interfere with adequate removal of the soft part via endoscopic endonasal approach with the hard calcification untouched. Postoperative course of all patients was uneventful. Long term follow-up (median interval of 49 months, range 8-70 months) showed that no recurrence occurred.

CONCLUSIONS

Although relatively rare, calcified nonfunctioning pituitary adenoma should be kept in mind to avoid making a wrong preoperative diagnosis. Given various calcification types, multiple surgical tactics is required accordingly. Extra-pseudocapusual resection via endoscopic endonasal approach is helpful for the resection of both adenoma and calcification.

Differential diagnosis of sellar masses

The differential diagnosis of nonpituitary sellar masses is broad; differentiating among potential etiologies may not always be straightforward because many of these lesions, tumorous and nontumorous, may mimic the clinical, endocrinologic, and radiologic presentations of pituitary adenomas. This article provides an overview of the clinical and radiographic characteristics of both pituitary tumors and the nonpituitary lesions found in the sellar/parasellar region and discusses, in detail, the specific nonpituitary origins of the sellar masses.

Calcified pituitary adenoma associated with severe hyperprolactinemia. Case report

A patient with a completely calcified chromophobe adenoma is reported. Endocrine evaluation revealed very high prolactin levels. Such extensive calcifications in prolactin-secreting adenomas are extremely rare. The possible pathogenetic mechanisms of this association are discussed.

Calcifications in pituitary adenomas

In a surgical series of 755 pituitary adenomas, 51 cases (6.75%) showed intratumoral calcifications on microscopic examination and 13 of these were visible on roentgenographic examination (1.72%). Thirty-eight of these 51 cases were prolactinomas, the highest incidence being in male patients. There was no correlation between age, sex, levels of hormone, size of the tumor, and the presence of calcifications. Four patterns of radiological calcifications were encountered. Histologically, the calcifications were most frequently found within the tumor masses. Their rare occurrence within fibrous or degenerative areas speaks against their dystrophic nature. Previously reported calcified bodies in fetal and newborn pituitaries and the recently described physiological hyperprolactinemia in early infancy suggest a possible hormonal influence in the genesis of calcifications in prolactinomas.

Characterization of a pituitary stone

Calcification of the pituitary is unusual and functional studies of such cases have not been previously reported. We have been able to document persistent prolactin secretion both in vivo and in vitro in a patient with a severely calcified pituitary adenoma ("pituitary stone"), and have also documented prolactin granules within the calcified tissue mass. Normal menstrual function was restored after surgical removal of the "stone," and galactorrhea subsided although the prolactin response to thyrotropin-releasing hormone (TRH) remained abnormal. Two years after surgery the menstrual cycle has remained regular, but galactorrhea has recurred, emphasizing the need for prolonged follow-up in patients with prolactin-producing adenomas, despite apparent surgical cure. The in vitro studies showed that human pituitary tissue is secretory in culture and thus may serve as a useful tool for physiologic studies of the pituitary cell.

An unusual case of chromophobe adenoma with conspicuous calcifications

Abnormal calcification on skull films in the region of the sella turcica is not commonly found with chromophobe adenoma. A patient with such calcification in a verified chromophobe adenoma is presented. From the literature the incidence of calcification in these tumours is reviewed. The importance of considering a chromophobe adenoma in the differential diagnosis of parasellar calcification from the surgical point of view is mentioned.