Indian Journal of Pathology and Microbiology

: 2020  |  Volume : 63  |  Issue : 3  |  Page : 491--492

Spherical amyloid deposition in prolactinoma

Monika Gupta, Nitika Grover, Rajeev Sen 
 Department of Pathology, Pt BDS, PGIMS, UHS, Rohtak, Haryana, India

Correspondence Address:
Monika Gupta
17/8 FM, Medical Enclave, Rohtak, Haryana

How to cite this article:
Gupta M, Grover N, Sen R. Spherical amyloid deposition in prolactinoma.Indian J Pathol Microbiol 2020;63:491-492

How to cite this URL:
Gupta M, Grover N, Sen R. Spherical amyloid deposition in prolactinoma. Indian J Pathol Microbiol [serial online] 2020 [cited 2020 Oct 27 ];63:491-492
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Pituitary adenomas (PAs) are peptide hormone-secreting tumor of the pituitary gland. On the basis of size, PAs are divided traditionally into microadenomas (dimension <1 cm) and macroadenomas (dimension ≥1 cm).[1] Normal and neoplastic endocrine tissue secret peptide hormones can accumulate amyloid in various systemic and localized conditions. Localized endocrine amyloid deposits, as seen in pituitary gland, are also termed amine precursor uptake and decarboxylation amyloid because the cells that secrete it share the property to handle precursors of biogenic amines caused by twisted beta plated sheet fibril accumulation forming micellar structures of beta protein. First described in 1972, amyloid deposits are seen up to 71% of pituitary tumors. Amyloid deposition can be stellate or perivascular and spherical type. They are relatively common in prolactin (PRL) secreting adenomas but can also occur in growth hormone (GH) and corticotrophin secreting or nonfunctional adenomas.[2],[3] However; spherical form is exclusively seen in prolactinomas. We report a case of a large prolactinoma with extensive spherical amyloid depositions which was mimicking calcification on radiological imaging.

A 58-year-old female presented with history of progressive loss of vision with visual field defects and headache from 9 months. Ophthalmic examination revealed decreased vision in both eyes with no signs of optic atrophy. Magnetic resonance imaging revealed a large intrasellar mass with calcification and suprasellar extension suggesting of giant PA. Hormonal analysis revealed elevated levels of serum prolactin of 3600 ng/mL (normal 4.04–15.2 ng/mL) and normal levels of GH luteinizing hormone and follicle stimulating hormone. The patient underwent transnasal-sphenoidal approach adenomectomy. Intraoperatively, tumor found to have variable consistency with areas of calcifications. The postoperative period was uneventful and the vision disturbances improved. No medical treatment was given to the patient. Pathological examination revealed grossly multiple grey white to gray brown soft tissue pieces altogether measuring 1.5 × 1.5 × 1 cm. On microscopic examination of hematoxylin and eosin stained section showed a monotonous population of round to polygonal tumor cells with variable amounts of eosinophilic cytoplasm admixed with multiple amorphous homogenous, extracellular, and spherical eosinophilic masses. No calcification seen in the biopsy. These masses stained positive with Periodic Acid Schiff (PAS) and Congo red stain and showed apple green birefringence under polarized light [Figure 1] and [Figure 2]. These results were consistent with an amyloid-producing prolactinoma.{Figure 1}{Figure 2}

PA apparently arise from one pituitary cell type or the other and is the most common tumour of pituitary gland and account for 10–25% of all intracranial tumors.[4] Only 25 cases of histologically proven spherical amyloid body in PA have been reported in the literature. All tumors were prolactinomas except one case in which GH was raised.[2]

Two different histological patterns of amyloid deposit in PAs have been described, the stellate and the spherical, respectively. Stellate amyloid is more common and found in all endocrine types of PA and is characterized by stellate, around blood vessels, and intercellular deposits in a fibrillary or crystalloid microstructure pattern.[5] Spherical type, a rare entity seen exclusively in PRL-producing adenomas, as seen in our case, consists of an accumulation of coral-like sphere with variable diameters (40–1500 mm).[2]

The etiopathogenesis of extensive amyloid deposits in prolactinomas is still unknown. Amyloid fibril protein is derived from proteolysis of a large precursor protein. Normally in our body misfolded proteins are degraded intracellularly in proteasomes and extracellularly by macrophages. But in amyloidosis this quality control mechanism fails either because of enzyme defect or structure abnormality. There are various postulated mechanisms of amyloidosis described in the literature. First, amyloid deposition in PA is associated with local conditions such as naturally developed degenerative changes; second, mesenchymal histiocytes produce the amyloid by an unknown process; third, abnormal processing of prolactin or the prohormone produced by the adenoma cells; and fourth degradation of secretory granules in vesicles containing amyloid fibrils responsible for the formation of amyloid. Studies also suggested that amyloid accumulation is enhanced in adenomas treated with dopamine antagonist compared with those not treated and long-term treatment also results in extensive tumoral fibrosis.[2],[3]

In our patient, the PA was extending into the sphenoid sinus which is usually seen with macroadenoma with calcification. We are also of the opinion that deposition of amyloid may be related with the PRL synthesis process and may be enhanced by in prolactinoma, as seen in our case. Our patient was not treated with dopamine agonist. There are different treatment approaches in the literature for PA with amyloidosis. Some preferred the medical treatment others says that surgical resection is better as the dopamine agonists enhance the amyloid deposition.[6]

Coral like (spherical) amyloid deposits in PA are rare and found exclusively in prolactinomas. Since these patients do not show any specific clinical and serological features, preoperative suspicion of amyloid deposition is difficult. Analysis of the reported literature and patient prognosis may help the clinicians in deciding patient management.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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