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Leiomyoma of deep soft tissue


Leiomyoma of deep soft tissue is a rare benign soft tissue tumor that occurs in the deep subcutaneous tissues or in skeletal muscle of the extremities.

The sexes are equally affected.
A slow growing mass with minimal tenderness.
Calcifications are frequently present within the lesion.
Local, complete excision ( marginal margin) is curative.
Complete Information on this Tumor
Introduction and Definition: 

Leiomyoma of deep soft tissue is a very rare, benign soft tissue tumors that arise in the deep subcutaneous tissues or in skeletal muscle. The sexes are equally affected. The tumor occurs most commonly in the extremities.

Incidence and Demographics: 
The tumor is very rare. Based on the small number of cases in the literature, men and women are equally affected. the age at diagnosis may be from 14 to 62 years, mean 37 years.
Symptoms and Presentation: 

A slow growing, minimally painful mass in the deep subcutaneous tissues of the extremities.

X-Ray Appearance and Advanced Imaging Findings: 
The soft tissue lesion may have amorphous calcifications.
Differential Diagnosis: 
Synovial sarcoma, ancient schwannoma, low grade leiomyosarcoma
Preferred Biopsy Technique for this Tumor: 
Histopathology findings: 
The tumors are well-defined and have a pseudocapsule. The cells are spindle shaped and appear in intersecting fascicles. The nuclei are elongated with rounded ends, and the cytoplasm is tapered and eosinophilic. Mitotic figures are very rare, less than one per 50 HPF's. There may be hyaline or myxoid stroma with degeneration. There may be nodules resembling necrobiotic granuloma or giant rosettes. Immunohistochemical staining is positive for desmin in all cases.
Treatment Options for this Tumor: 
Marginal excision is curative.
Preferred Margin for this Tumor: 
Outcomes of Treatment and Prognosis: 
Complete excision is associated with a low likelihood of recurrence. Prognosis is excellent with appropriate treatment.
Special and Unusual Features: 
A very rare tumor, with around twenty cases in the worldwide literature.
Suggested Reading and Reference: 
Leiomyoma of deep soft tissue. Clinicopathologic analysis of a series. Kilpatrick SE, Mentzel T, Fletcher CD. Am J Surg Pathol. 1994 Jun;18(6):576-82. Do leiomyomas of deep soft tissue exist? An analysis of highly differentiated smooth muscle tumors of deep soft tissue supporting two distinct subtypes. Billings SD, Folpe AL, Weiss SW. Am J Surg Pathol. 2001 Sep;25(9):1134-42.