Unicentric

Unicentric is an adjective used mainly in medical and biological contexts to describe a condition, disease, or growth that originates from or involves a single site or organ. The term contrasts with “multicentric,” which denotes involvement of multiple separate sites. In pathology, unicentricity often carries significant implications for diagnosis, management, and prognosis.

A well‑known example is unicentric Castleman disease (uCD), a rare lymphoproliferative disorder of the B‑cell lineage. In uCD, a localized mass of lymphoid tissue, usually in the mediastinum or elsewhere in the body, shows distinctive histological features such as hyaline‑vascular or plasmacytic changes. Unlike multicentric Castleman disease, uCD typically presents without systemic symptoms or significant laboratory abnormalities. The standard treatment is complete surgical excision of the lesion, which frequently results in cure and a normal life expectancy.

Unicentric tumors can also occur in other organ systems. Unicentric hepatic hemangiomas and unicentric dermal Merkel cell carcinoma are instances where the lesion is confined to one location. In such cases, localized therapy such as surgery, ablation, or radiation is usually sufficient, whereas multicentric disease often requires systemic therapy.

Clinicians determine unicentricity through imaging modalities—CT, MRI, PET scans—combined with biopsy. Accurate classification guides therapeutic decisions: local versus systemic treatment, monitoring frequency, and prognostic counseling.

The concept of unicentric versus multicentric can also apply beyond oncology, for example in autoimmune disorders where a single organ shows pronounced inflammation. In all settings, recognition of unicentric patterns is important for tailoring patient care and predicting outcomes.