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infantile myofibroma

Tuesday 9 December 2003

solitary myofibroma, infantile myofibromatosis. Ent. Wiliams and Schrum, 1951. Nom. Chung and Enzinger, 1981.


- Myofibroma: Biphasic, myoid nodules with gray stroma, primitive spindled cells

Digital case

- Case 205 (HPC:205) : Infantile myofibroma


- sporadic cases
- familial cases (8600777)

Localization of tumors

- orbital region (11410140)
- central nervous system (12720031), spinal canal (9703012)
- oral region (10792791), gingiva (12472999)
- bone
- muscle
- viscera (heart, lungs, liver, gastrointestinal tract (2672792), bile ducts and pancreas (3185365), endocrine organs)
- subcutaneous tissue, soft tissues
- digestive tract

  • intestinal infantile myofibromatosis

Microscopical synopsis

Biphasic pattern
- fascicles of spindle cells with abundant eosinophilic cytoplasm that resembled smooth muscle
- more primitive spindled cells associated with a hemangiopericytoma-like vascular pattern

- interlacing fascicles of myofibroblasts with abundant eosinophilic cytoplasm
- variable necrosis
-  calcifications in some sites
- hemangiopericytoma-like features
- angiocentric and perivascular growth of myofibroblasts (+/-) (8597844)


- vimentin+
- smooth muscle actin+


- solitary myofibromatosis
- systemic myofibromatosis, multicentric myofibromatosis

  • congenital generalized myofibromatosis (CGMF) (8597844)
  • aggressive infantile myofibromatosis (3784986)

Two types can be distinguished; the solitary type, defined by the presence of one nodule in the skin, muscle, bone or subcutaneous tissue; and the multicentric type which can be divided into two sub-types.

In the first sub-type the lesions are multicentric but without visceral involvement, while in the second, visceral involvement is present.

- adult-type myofibroma

Associations (sporadic)

- neonatal hemochromatosis (11196755)
- Turner syndrome (9821432)
- arterial fibromuscular dysplasia (15455480)


- del(6)(q12q15) (10425309)
- monosomy 9q (15365831)
- trisomy 16q (15365831)


The prognosis of the disease depends on whether visceral involvement is present. Solitary and multicentric nodules without visceral involvement usually have excellent prognosis with spontaneous regression of lesions within 1 to 2 years of diagnosis.

Visceral lesions are associated with a significant morbidity and mortality, resulting from vital organ obstruction, failure to thrive, or infection. Death in these cases often occurs at birth, or soon after, and is usually due to cardio-pulmonary or gastrointestinal complications. However, multicentic type of infantile myofibromatosis with visceral involvement can spontaneously regress. (11510506)

Differential diagnosis

- low-grade myofibroblastic neoplasms

- fibromatoses

  • composite fibromatoses

- congenital fibrosarcoma (infantile fibrosarcoma)
- inflammatory myofibroblastic tumor
- fibrous fibrohistiocytic tumors
- solitary fibrous tumor
- nodular fasciitis
- desmoplastic fibroblastoma (collagenous fibroma)
- smooth muscle tumors

  • leiomyoma
  • leiomyosarcoma

- neurogenic tumors

- juvenile xanthogranuloma

See also

- hemaniopericytomatous pattern


- Granter SR, Badizadegan K, Fletcher CD. Myofibromatosis in adults, glomangiopericytoma, and myopericytoma: a spectrum of tumors showing perivascular myoid differentiation. Am J Surg Pathol. 1998 May;22(5):513-25. PMID: 9591720

- Mentzel T, Calonje E, Nascimento AG, Fletcher CD. Infantile hemangiopericytoma versus infantile myofibromatosis. Study of a series suggesting a continuous spectrum of infantile myofibroblastic lesions. Am J Surg Pathol. 1994 Sep;18(9):922-30. PMID: 8067513

- Dictor M, Elner A, Andersson T, Ferno M. Myofibromatosis-like hemangiopericytoma metastasizing as differentiated vascular smooth-muscle and myosarcoma. Myopericytes as a subset of "myofibroblasts". Am J Surg Pathol. 1992 Dec;16(12):1239-47. PMID: 1463097