Aggressive fibromatosis: is PET-CT useful in lesion characterization?

We present a case of a 64-year-old man with a hard painless lump in his left calf. The solid and partially hypervascular appearance on ultrasound, the infiltrative appearance, lesion heterogeneity and heterogeneous enhancement pattern on Magnetic Resonance Imaging (MRI) were suspicious for a soft tissue sarcoma. Moreover, PET-CT demonstrated FDG-avidity. Despite these aggressive imaging features, histopathology revealed a benign but locally aggressive desmoid tumour. The radiologist should be aware that PET-CT is not always helpful as an additional tool for differentiation between malignant and benign soft tissue lesions. Intralesional bandlike areas of low signal intensity on all pulse MR sequences and intimate relationship with the muscle fascia are more useful clues to the diagnosis of this soft tissue lesion.

We are reporting here a case of DT that presented as an intra-abdominal mass with pelvic extension in a patient who underwent hysterectomy for fibroid uterus seventeen years ago. A clinical diagnosis of ovarian malignancy was made. Ovarian tumour markers for surface epithelial and germ cell tumours were negative. Imaging studies suggested DT and the same was excised surgically. A histopathological diagnosis of DT was made and confirmed with immunohistochemistry (IHC) markers. DT should always be considered especially in female patients with previous history of surgery.

Crago AM, Denton B, Salas S, Dufresne A, Mezhir JJ, Hameed M, Gonen M, Singer S, Brennan MF.

Wang Y, Cui NY, Li L, Zhang R, Hao YZ, Xue LY, Zhou CW, Jiang YX.

Ogawa N, Iseki H, Tsunozaki H, Hayashi M, Baba H, Matsuyama T, Uetake H, Sugihara K

Mullen JT, Delaney TF, Rosenberg AE, Le L, Iafrate AJ, Kobayashi W, Szymonifka J, Yeap BY, Chen YL, Harmon DC, Choy E, Yoon SS, Raskin KA, Hornicek FJ, Nielsen GP.