Amyloid deposits in pituitaries and pituitary adenomas: Immunohistochemistry andin situ hybridization

Abstract

The patterns of deposition and immunoreactivity of interstitial amyloid were studied in 11 pituitary glands obtained at autopsy and 9 surgically resected pituitary adenomas using Congo red staining and a panel of antisera directed against 5 major amyloid fibril proteins and all pituitary hormones. The deposition pattern of amyloid in pituitary glands differed from that in adenomas but all amyloid deposits showed an immunostaining with anti-amyloid X-light chain. The remaining antisera were immunonegative. In situ hybridization using an oligodeoxyribonucleotide-probe complementary to the mRNA coding for the constant region of human X-light chain yielded no hybridization signals in the pituitaries or pituitary adenomas, excluding local synthesis and secretion of immunoglobulins. Since no case studied suffered from generalized AX-amyloidosis and adsorption of immunoglobulins to the unknown amyloid fribril protein of the pituitary seems to be unlikely, crossreaction of the polyclonal antisera with an undefined antigen is probable. The similar immunostaining properties of amyloid deposits in "normal" pituitaries and pituitary adenomas suggest they both originate from the same precursor protein.

Pathohistological classification of pituitary tumors: 10 years of experience with the German Pituitary Tumor Registry

“…Calcifications of psammoma body type can be found. Amyloid derived from PRL (endocrine amyloid) is demonstrable in up to 48% of adenomas (50,51). Immunostaining for PRL is often concentrated in the Golgi areas (so-called Golgi pattern) (6,40).…”

Amyloid in surgical pathology

“…Even antibodies generated using amyloid fibril proteins as immunogen may be misleading. We have shown in our own immunohistochemical studies that an antibody directed against l-light chain amyloid deposits cross reacts "specifically" with amyloid of prolactin origin in pituitaries and pituitary adenomas [92].…”

“…Amyloid may also be found in the absence of clinical symptoms. [75], tumors of the skin (e.g., basal cell carcinomas and seborrheic keratosis) [76], cornea, meningiomas [29], pituitary and their adenomas [92], odontogenic tumors [6], medullary cancer of the thyroid, neuroendocine tumors of the lung [1], cardiac atria [101], intima and media of arteries [46,120], mesenteric and portal veins [95], islets of Langerhans [116], microcystic adenoma of the pancreas [113], gastroenteropancreatic endocrine tumors (i.e., insulinomas, vipomas, somatostatinomas) [16,74,119], renal angiomyolipoma [112], pheochromocytomas [107] and seminal vesicles [83]. Local deposits derived from immunoglobulin light chains (AL amyloid) have been found in various organ and tissue sites, often presenting as "amyloidoma".…”

Amyloidoza plamkowata jako powikłanie makrogruczolaka prolaktynowego przysadki — nowy związek kliniczny

“…Type-2 diabetes, perhaps the most common form of localised amyloidosis, is characterised by deposition of amylin (islet amyloid polypeptide) in the pancreas [11]. However, it is important to realise that the precursor protein(s) of both macular amyloidosis and prolactinoma remain unknown [11].…”

“…Type-2 diabetes, perhaps the most common form of localised amyloidosis, is characterised by deposition of amylin (islet amyloid polypeptide) in the pancreas [11]. However, it is important to realise that the precursor protein(s) of both macular amyloidosis and prolactinoma remain unknown [11]. The temporal profile of the disease characterised by symptoms suggestive of pituitary macroadenoma preceding the onset of macular amyloidosis with resolution of symptoms of macroprolactinoma, accompanied by reductions in circulating prolactin levels, and concomitant improvement in macular amyloidosis with cabergoline therapy, may suggest some link between macroprolactinoma and macular amyloidosis.…”