Myofibroblastoma: Report of a Rare Entity in the Pediatric Population

Abstract

Fibroblastic and myofibroblastic tumors constitute an important group of neoplasms in children and adolescents. These span the full spectrum of clinical behavior, ranging from benign to intermediate and malignant. We report a case of a benign mesenchymal tumor with myofibroblastic differentiation in a 9-year-old girl arising in the left groin that met the histologic features described for myofibroblastoma in adults. Two types are recognized in adults: angiomyofibroblastoma and mammary-type myofibroblastoma of soft tissue. Our case shared features of both these subtypes but was not typical of either one, and we therefore designated our case simply as "myofibroblastoma." Our case showed expression of estrogen receptor protein, which is characteristic of adult lesions, but not a deletion of 13q14, as has been reported in some adult cases. In the English-language literature, only 6 cases have been reported in patients under 21 years of age, and all but 1 were teenagers. Pediatric surgeons, oncologists, and pathologists should be aware that such a benign entity can occur in this patient population and could be confused with other lesions, including malignant ones.

Angiomyofibroblastoma-Like Tumour of the Scrotum, a Case Report in a Child

“…The youngest adult case of AMF-like tumour was reported by Bouhajja et al in 2017 in a 27-year-old patient [7]. Chami et al reported a case of benign mesenchymal tumour with myofibroblastic differentiation in a 9-year-old girl arising in the left groin that met the histologic features described for myofibroblastoma in adults [8]. Treatment is surgical resection with wide excision to tumour-free margins to prevent recurrent disease.…”

Mammary-type myofibroblastoma of the psoas

“…The differential diagnosis for extra-MTMF includes neoplasms of a benign (benign nerve sheath tumour, solitary fibrous tumour, leiomyoma, spindle cell lipoma (SCL), cellular angiofibroma, angiofibroblastoma, angiomyxoma and soft tissue perineurioma) and malignant (liposarcoma, dermatosarcoma protuberans) nature 14 17. However, extra-MTMF is most often confused with SCL since they are both composed of CD34 positive spindle cells interspersed with adipose tissue 5 17.…”

“…However, in this patient's case, the mass was relatively encapsulated. They are typically composed of spindle-shaped cells arranged in fascicles, interspersed within a collagenous stroma 2 4 14 17–19. There is also a variable adipocytic component 2 18.…”

Clinicopathologic evaluation of myofibroblastoma: A study in two hospitals

“…After that, superficial myofibroblastoma of the lower female genital tract was initially described in 2001 [ 2 ]. Due to the rarity of the tumor, only a few case reports or case series have been reported [ 3 4 5 ]. Recently, the wider anatomic distribution of myofibroblastoma was reported [ 6 ] and is now increasingly recognized.…”