Leiomyoma of deep somatic soft tissue

Definition

A benign tumour of deep tissues, composed of smooth muscle. Deep somatic leiomyomas should probably be considered separately from those occurring in the retroperitoneum and abdominal cavity.

Epidemiology

There is no gender predominance2.

Clinical features

These tumours most commonly develop in the thigh.

Macroscopic appearances

Well circumscribed, white to tan-grey, often rubbery.

Histopathology

Composed of mature smooth muscle cells with eosinophilic cytoplasm and blunt-ended nuclei. Degenerative nuclear changes may occur2. A few cases show epithelioid cells. There is variable stromal hyalinisation. Stromal calcification is common. multiple necrobiotic granuloma-like nodules resembling giant rosettes have been reported2.

Immunohistochemistry

SMA: positive
Desmin: positive
h-Caldesmon: positive
S-100: negative
Oestrogen receptor: negative1
Progesterone receptor: negative1

Differential diagnosis

References

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

1Billings, S. D., A. L. Folpe, et al. (2001). "Do leiomyomas of deep soft tissue exist? An analysis of highly differentiated smooth muscle tumors of deep soft tissue supporting two distinct subtypes." Am J Surg Pathol 25(9): 1134-42.

2Kilpatrick, S. E., T. Mentzel, et al. (1994). "Leiomyoma of deep soft tissue. Clinicopathologic analysis of a series." Am J Surg Pathol 18(6): 576-82.

This page last revised 29.6.2004.