The pituitary gland is an uncommon site of tumor metastasis and is predominantly associated with malignancies of the lung and breast. Metastatic involvement of the pituitary gland in lung cancer (LC) typically indicates advanced disease and is associated with poor prognosis and pituitary insufficiency, which often remains underdiagnosed and significantly affects quality of life and survival. We present four cases of pituitary metastasis (PM) originating from LC, characterized by distinct histological subtypes, variable timing from initial diagnosis, and diverse clinical manifestations. Clinical presentation was heterogeneous: two patients had involvement of both pituitary lobes with multiple pituitary hormone deficiencies, one had anterior lobe involvement with anterior pituitary deficiency following immune checkpoint inhibitor-associated hypophysitis, and one remained asymptomatic. Therapeutic approaches included partial surgical resection followed by radiotherapy in two patients and radiotherapy alone in the other two; all patients continued systemic antineoplastic therapy and received hormone replacement as indicated. Mean overall survival was 7.5 months. PM can occur across all histological subtypes of LC and typically signifies advanced disease with poor prognosis. Early identification and appropriate management of hypopituitarism may improve quality of life and clinical outcomes.

Small leucine-rich proteoglycans (SLRPs) are an important group of molecules in the extracellular matrix (ECM) that are involved in regulating collagen assembly, tissue homeostasis, and cell signalling pathways. Among them, Decorin represents the proto-type member and plays a central role in maintaining ECM integrity, regulating fibrosis, and controlling tumor progression. This review examines the structural and functional biology of SLRPs, with a special focus on Decorin, highlighting its involvement in fibrotic diseases, degenerative disorders and the tumor microenvironment. Decorin acts as a multifunctional regulator through its interactions with TGF-β, various tyrosine kinase receptors, and multiple ECM components, carrying out anti-fibrotic, anti-angiogenic, anti-cancer, and tumour-suppressive functions. Additionally, factors such as the contribution of SLRPs to the desmoplastic response of tumors, their potential use as biomarkers for extracellular matrix remodelling, and the emerging therapeutic prospects based on administering recombinant Decorin, gene therapies, mimetic molecules, and strategies targeting the ECM. Overall, SLRPs, especially Decorin, stand out as key molecules in integrating structural and molecular signals and as promising diagnostic and therapeutic targets in fibrotic and neoplastic diseases.