Silent corticotroph adenomas

Abstract

Silent corticotroph pituitary adenomas (SCA) are defined as pituitary adenomas showing positive staining for adrenocorticotrophic hormone in immunohistochemical studies, but not associated with perioperative clinical or laboratory features of hypercortisolaemia. They account for 1.1-6% of surgically removed pituitary adenomas. Currently, two distinct pathologic subtypes of SCA are recognised. Their pathogenesis remains unclear. They present with local mass effects (headache, visual deterioration, cranial nerve palsies, endocrine dysfunction). The lack of manifestations of cortisol excess has not been conclusively explained. In surgical series, most tumours are macroadenomas with suprasellar extension present in 87-100% of the cases; this is in contrast to Cushing's disease, which is mostly attributed to microadenomas. Surgery remains the main therapeutic approach. Attempts to identify predictors of recurrence have not been successful. Management and follow-up protocols should be planned taking into account their potential aggressive behaviour, particularly upon recurrence. The development of florid pituitary Cushing's syndrome and local recurrence followed by metastatic disease (occasionally outside the central nervous system) have been rarely reported. Adenomas corticotróficos silenciosos (ACS) são definidos como adenomas hipofisários que apresentam coloração positiva para o hormônio adrenocorticotrófico em estudos imuno-histoquímicos, mas não são associados com achados clínicos ou laboratoriais peri-operatórios de hipercortisolemia. São responsáveis por 1,1-6% dos adenomas hipofisários removidos cirurgicamente. Atualmente, dois subtipos patológicos distintos de ACS são reconhecidos, mas sua patogênese permanece obscura. Eles se apresentam com efeitos de massa local (cefaléia, deterioração visual, paralisia de nervos cranianos, disfunção endócrina). A ausência de manifestações de excesso de cortisol não é suficientemente explicada. Em séries cirúrgicas, a maioria dos tumores são macroadenomas com extensão suprasselar, presente em 87-100% dos casos, em contraste com a doença de Cushing, que é principalmente atribuída a microadenomas. A cirurgia continua a principal ação terapêutica. A tentativa de se identificar preditores de recorrência tem sido mal sucedida. Protocolos de manejo e acompanhamento devem ser planejados levando-se em consideração o seu comportamento potencialmente agressivo, particularmente na recorrência. Raramente tem sido reportado o desenvolvimento de síndrome de Cushing hipofisária florida e recorrência local, seguida de doença metastática (ocasionalmente fora do sistema nervoso central).

Pituitary Incidentaloma: An Endocrine Society Clinical Practice Guideline

“…However, some of the Task Force members often measure ACTH because a small percentage of incidentalomas may be silent corticotroph tumors (34), and occasionally plasma ACTH levels are elevated in patients harboring these tumors despite the lack of clinical manifestations of cortisol excess (34). …”

European Society of Endocrinology Clinical Practice Guidelines for the management of aggressive pituitary tumours and carcinomas

“…Rarely, initially silent corticotroph tumours may evolve to secrete ACTH after many years of follow-up, and this transformation may also herald more aggressive tumour behaviour (42,43,44,45). Silent subtype III or plurihormonal silent tumours (40) also may exhibit a more aggressive clinical course compared with silent gonadotroph tumours (46).…”

Management of nonfunctioning pituitary incidentaloma

“…Certain teams prescribe ACTH assay [44]. But ACTH may be elevated without biological evidence of cortisol hypersecretion, hindering indications.…”