granulomatosis

Granulomatosis refers to a pathological process characterized by granuloma formation, a structured aggregation of immune cells that develop in response to persistent antigenic stimulation. Granulomas are composed mainly of macrophages that transform into epithelioid cells and multinucleated giant cells, often surrounded by lymphocytes and fibrous tissue. They may be caseating (necrotizing) as seen in tuberculosis, or noncaseating as seen in sarcoidosis or other conditions.

Causes are diverse, including infectious agents such as Mycobacterium tuberculosis and certain fungi; noninfectious inflammatory diseases such as granulomatosis with polyangiitis, sarcoidosis, and Crohn's disease; and reactions to foreign material or implants. The term is used broadly for granulomatous inflammation in various organs.

Clinical manifestations depend on the organs involved; lungs and the respiratory tract, skin, lymph nodes, and liver are commonly affected. Symptoms can include cough, chest pain, dyspnea, fever, night sweats, and weight loss, as well as skin nodules or generalized fatigue. Diagnosis typically uses imaging and tissue biopsy to identify granulomas and to exclude infection; microbiological studies are essential to rule out infectious etiologies. Serum markers may aid evaluation: ACE levels can be elevated in sarcoidosis; ANCA may be positive in granulomatosis with polyangiitis.

Management targets the underlying cause. Infectious granulomas require antimicrobial therapy; noninfectious granulomatous diseases may respond to corticosteroids and immunosuppressants, with newer therapies targeting inflammatory pathways. Prognosis varies with etiology and organ involvement; timely treatment improves outcomes in inflammatory granulomatous diseases.

See also: granuloma, granulomatous inflammation, granulomatosis with polyangiitis, sarcoidosis.