Leiomyosarcoma of the head and neck

Definition

Leiomyosarcomas of the head and neck may involve the neck, maxilla, buccal area, sinuses, nose or pharynx.

This is a rare tumour

The features are those of leiomyosarcoma as seen at other sites, with a tendency to have an inflammatory component.

Spindle cell carcinoma: frequently polypoidal and mucosa-based. There may be an in-situ or invasive epithelial component and there is usually, but not invariably, cytokeratin positivity. There may be actin positivity. Leiomyosarcomas may also show focal cytokeratin positivity.
Spindle cell melanoma
Sarcoma:
- myofibrosarcoma; has a proclivity for the head and neck. Nuclei are tapered. There is positivity for muscle markers. Ultrastructurally, myofilaments are scanty and peripheral rather than diffusely cytoplasmic.
- fibrosarcoma; there is a herringbone pattern and nuclei are tapered. Muscle markers are only expressed very focally; S-100 and cytokeratins are negative.
- malignant peripheral nerve sheath tumour
- malignant fibrous histiocytoma
- rhabdomyosarcoma; occur in the head and neck in childhood. There is positivity for myogenin and myoD1.
- synovial sarcoma
Nodular fasciitis; more common in the extremities.
Intravascular fasciitis: prone to occur in the head and neck.
Inflammatory myofibroblastic tumour: the inflammatory infiltrate is predominantly of plasma cells and nuclei are tapered. there is usually positivity for smooth muscle actin and muscle-specific actin, less often for desmin. There may be positivity for cytokeratin and ALK.
Leiomyoma: rare in the head and neck.
Myofibroma; often presents in the head and neck. It consists of small dark cells in a haemangiopericytoma-like pattern.
Solitary fibrous tumour
Benign nerve sheath tumour

The behavior of smooth muscle tumours is site-specific. Leiomyosarcomas of the head and neck are aggressive tumours.

This page last revised 6.4.2003.