nonfluctuant

Nonfluctuant is a medical descriptor used during physical examination to describe a swelling, lump, or lesion that does not yield a fluctuant wave on palpation. Fluctuation refers to the palpable movement of a liquid-filled cavity, such as an abscess, under the finger when pressed. A nonfluctuant lesion therefore lacks a freely movable fluid collection beneath the surface.

However, nonfluctuant does not prove the absence of infection or fluid. Abscesses can be nonfluctuant in early stages, when pus is thick or encapsulated, or when overlying edema or fibrosis restricts movement. Solid masses or lesions containing fibrous tissue or keratin can be nonfluctuant. Thus, the term is a descriptor, not a diagnosis, and must be interpreted in the clinical context.

Common scenarios include cellulitis or phlegmon presenting with swelling that is tender, warm, and nonfluctuant; solid tumors such as lipomas or fibromas; hematomas; cysts with thick walls or viscous contents. The finding prompts further assessment, including careful history, examination of size, borders, mobility, associated signs, and possibly imaging such as ultrasound or MRI to distinguish solid from cystic or fluid-filled processes. If abscess is suspected despite nonfluctuance, aspiration or imaging-guided drainage may be considered.

Management and differential: The descriptor itself does not dictate therapy; management depends on the underlying process. Nonfluctuant swelling due to cellulitis is usually managed with antibiotics and monitoring; solid masses may require surgical evaluation or biopsy if suspicious for malignancy. Imaging guidance and referral should be pursued for uncertain or concerning nonfluctuant lesions.

See also: fluctuation, abscess, cellulitis, mass lesion, ultrasound.