Acromegaly and histopathology.

Acromegaly is a chronic disorder caused by sustained excess of growth hormone (GH) and insulin-like growth factor-1 (IGF-1), most commonly due to GH-secreting pituitary neuroendocrine tumors (PitNETs), mainly limited to Pit-1 expressing lineages. Histopathology remains central to diagnosis, prognosis, and treatment planning. Among GH-secreting or somatotroph neoplasms, densely and sparsely granulated are the most relevant clinicopathological subgroups, as they show distinct morphological, radiological, and clinical profiles. Risk assessment is refined by combining routine histology with immunohistochemistry (IHC), including lineage factors, proliferative markers, and somatostatin receptor (SSTR) subtypes, as well as selected molecular tests. Some assays, such as standardized evaluation of SSTR expression, still require further validation. Radiological signs of invasion complement tissue findings and contribute to practical grading systems. Optimal care requires a multidisciplinary approach that integrates endocrine evaluation, high-quality MRI, and expert neuropathology, essential not only for routine care but also for recognizing atypical presentations of acromegaly, such as pituitary hyperplasia, or ectopic growth hormone-releasing hormone (GHRH) or GH secretion. The integration of clinical, pathological, and molecular information provides the foundation for accurate diagnosis and personalized therapy in acromegaly.