F 33, abdominal wall soft tissue mass,7.5 x6x3 cm, 61 g, pink-white, whorled, trabecular cut surface.

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Diagnosis: 
Abdominal desmoid tumor (Abdominal desmoid fibromatosis)
Comment: 

Mostly in females, 15-40 yrs, frequently during or soon after pregnancy.
Deeply infiltrative fibroproliferative lesion involving fascia and muscle of abdominal wall.
Rarely associated with familial polyposis/Gardner syndrome.
Overall recurrence: 30%

Pathology:

Cytologically bland, spindly fibroblastic cells in fascicles
or haphazardly infiltrating into the fascia and skeletal
muscle.
Low to moderate cellularity, no or few normal mitoses,
no atypical mitosis.
No necrosis or hemorrhage.

Immunostaining:
Actin: Positive, Desmin: Focally positive, Beta catenin:
Positive, Vimentin: Positive.
CD34: Negative, S-100: Negative, Cytokeratin: Negative.