Pheochromocytoma is a rare neuroendocrine tumor that arises from chromaffin cells of the adrenal medulla and secretes excess catecholamines. Clinically, it presents with various symptoms, with a hallmark of treatment-resistant hypertension, often accompanied by paroxysmal episodes of headache, sweating, and palpitations. Although its overall incidence is low, pheochromocytoma should be considered in the differential diagnosis of young patients with refractory hypertension despite the use of multiple antihypertensive agents, particularly when secondary hypertension is suspected. We present the case of a patient who developed a hypertensive crisis and hemodynamic angina, ultimately diagnosed with malignant pheochromocytoma with hepatic and pulmonary metastases.

Opportunistic infections such as Pneumocystis jirovecii pneumonia (PJP) and thromboembolic complications are frequent and well-known manifestations in patients with advanced human immunodeficiency virus (HIV) infection. Their simultaneous presentation as the initial HIV diagnosis in a previously healthy patient is rare and represents a diagnostic and therapeutic challenge due to its potentially fatal nature.

This review paper, conducted between January and March 2025 and based on a comprehensive analysis of previous studies, investigates the function of members of the PAX gene family in human illnesses. PAX genes serve as critical regulators in the development of various tissues and organs, and mutations in these genes have been linked to a broad spectrum of genetic disorders and cancers. The research focused on the functions of individual PAX genes and their associations with disease phenotypes. For instance, mutations in PAX9 are linked to tooth agenesis, with the severity of dental anomalies depending on the mutation’s impact on DNA-binding capacity. Mutations in PAX2 have been associated with renal and ocular malformations, notably papillorenal syndrome, characterized by renal hypoplasia and optic nerve defects. Additionally, PAX4 and PAX6 are essential for the differentiation of pancreatic endocrine cells, and their mutations are implicated in various forms of diabetes. Moreover, aberrant expression of PAX genes is observed in several cancer types. PAX3 and PAX7 expression correlates with melanoma and sarcoma progression, while PAX2 and PAX8 are frequently expressed in Wilms tumor, a pediatric kidney cancer. These genes can influence tumor initiation, progression, or resistance mechanisms, though their exact oncogenic roles remain to be fully defined. The findings highlight the necessity for detailed characterization of PAX gene isoforms, mutation effects, and tissue-specific functions. Future investigations should also address the roles of PAX genes in adult tissue regeneration and further elucidate their contributions to developmental disorders and cancer biology.