Angioleiomyoma

Definition

A benign tumour composed of mature smooth muscle and vascular channels, occurring in the subcutis or deep dermis.

Synonyms

Angiomyoma, vascular leiomyoma

Epidemiology

This is a relatively common soft tissue tumour, usually occurring in the fourth to sixth decade. There is a female predominance2.

Clinical features

Usually found on the extremities, sometimes head or trunk. Almost all cases are solitary. Most are subcutaneous, some within the dermis. Lesions are commonly painful.

Macroscopic appearances

Lesions are well demarcated, grey-white or brown.

Histopathology

The smooth muscle cells are mature. Nuclear hyperchomasia may be a degenerative feature. There may be hyalinisation, calcification or myxoid change. Clusters of mature fat cells may be present.

Angioleiomyomas fall into three subtypes:

Solid or capillary; accounts for most cases on the legs. Vascular channels are numerous but small and slit-like.
Cavernous; accounts for most cases on the arms. The dilated vascular channels lack distinct muscular walls.
Venous; accounts for most cases on the head. The vascular channels have thick muscular walls.

Immunohistochemistry

SMA: positive
Desmin: positive
Vimentin: positive
Collagen type IV: positive
HMB45: negative.

The capsule commonly contains nerves positive for PGP9.5 and S-100.

Ultrastructure

Differential diagnosis

Pilar leiomyoma; tends to be multiple.
Angiomyolipoma: positive for HMB45.

Prognosis

Excision is almost always curative, with recurrence rare.

References

0 World Health Organization Classification of Tumours, Tumours of Soft Tissues and Bone, IARC Press 2002.

1 Hachisuga, T., H. Hashimoto, et al. (1984). "Angioleiomyoma. A clinicopathologic reappraisal of 562 cases." Cancer 54(1): 126-30.

2 Miettinen M,Fetsch JF Evaluation of biological potential of smooth muscle tumours. Histopathology 2006; 48:97-105

This page last revised 29.6.2004.