Multifocal occurrence of extra-abdominal desmoid type fibromatosis – A rare manifestation. A clinicopathological study of 6 sporadic cases and 1 hereditary case

• Published in: Annals of diagnostic pathology Vol. 35; pp. 38 - 41
• Main Authors: Bekers, Elise M., van Broekhoven, Danique L.M., van Dalen, Thijs, Bonenkamp, Johan J., van der Geest, Ingrid C.M., de Rooy, Jacky W.J., van Gorp, Joost M., Creytens, David H., de Leng, Wendy W.J., Scheijen, Blanca, Eijkelenboom, Astrid, Flucke, Uta
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.2018
• Subjects: Desmoid; Fibromatosis; Soft tissue tumors; Soft tissue tumors; Desmoid; Fibromatosis
• ISSN: 1092-9134; 1532-8198
• DOI: 10.1016/j.anndiagpath.2018.04.001

Desmoid-type fibromatosis, also called desmoid tumor, is a locally aggressive myofibroblastic neoplasm that usually arises in deep soft tissue with significant potential for local recurrence. It displays an unpredictable clinical course. β-Catenin, the genetic key player of desmoid tumors shows nuclear accumulation due to mutations that prevent its degradation leading to activation of Wnt signaling and myofibroblastic cell proliferation. The corresponding hot spot mutations are located in exon 3 of the CTNNB1 gene or alternatively, in the APC tumor suppressor gene, most often as a germline mutation. Multifocal desmoid tumors are very rare and clinical characteristics are poorly understood. Here we present six sporadic and one familial case of multifocal desmoid tumors. Four female and three male patients, aged between 7 and 30 years (mean 18.4 years) were identified in a cohort of 1392 cases. Tumors were located in (distal) extremities, thorax, breast, abdominal wall, shoulder, and neck. Four cases showed a CTNNB1 mutation and one an APC germline mutation. In two sporadic cases no CTNNB1 mutation was identified. Four patients showed (multiple) recurrences and one patient was lost to follow-up. In conclusion, multifocal desmoid tumors are a very rare disease and may occur in sporadic cases that are characterized by recurrent CTNNB1 mutations. However, the underlying pathogenesis of multifocal desmoid tumors remains poorly understood with often aggressive clinical behavior and challenging therapeutical management. •Multifocal desmoid tumors are very rare and clinical characteristics are poorly understood.•They may occur sporadically and show the same CTNNB1 mutations in different lesions, at least in our cases.•Circulation of mesenchymal progenitor cells including CTNNB1 mutated MPCs could explain multifocal development.•Multifocal desmoid tumors can behave aggressively.•The clinical management is challenging.