Lipomatous

Lipomatous is an adjective used in anatomy and pathology to describe tissue or lesions that are composed of, or resemble, adipose (fat) tissue. The term is derived from lipoma, a benign tumor of fat, with the suffix -ous indicating a characteristic related to or composed of fat.

Most commonly, lipomatous describes lipomas, which are well-circumscribed, slow-growing benign tumors made up of mature adipocytes. The opposite or malignant counterpart is the liposarcoma, a malignant adipocytic tumor that may show atypia and infiltrative growth.

In broader use, lipomatous changes can occur within other tissues, a concept known as lipomatous metaplasia or lipomatous infiltration. Examples include lipomatous hypertrophy of the interatrial septum in the heart, and lipomatous changes within soft tissues of the breast or other organs. These changes may be incidental findings on imaging or encountered during pathology.

Radiologic features help distinguish lipomas from liposarcomas: lipomas usually appear as well-defined, homogeneous fat-density lesions on CT or MRI, with signal characteristics consistent with fat and suppression on fat-saturation sequences. Liposarcomas may contain nonfatty components, thick septa, nodularity, or invasion. Definitive diagnosis requires histologic examination.

Management depends on the entity and symptoms. Most uncomplicated lipomas are monitored or excised for cosmetic or symptomatic reasons. Liposarcomas require oncologic evaluation and treatment, typically surgical resection with margins and staging.