A rare case of infantile myofibromatosis and review of literature

Abstract

Infantile myofibromatosis is a rare benign tumor-disease (1/400,000). Four different types have been reported in literature. The most commonly affected body areas are the head, the neck, and the trunk. We would like to present a rare case of a multicentric type with singular visceral involvement and a literature review of all case series with more than five patients. A 9-month-old boy presented with a swelling on the medial side of his proximal left tibia. The lesion which was present since birth, was well palpable, indolent, hard, and mobile in relation to the surrounding tissue. Radiographic films and ultrasound examination presented a pretibial soft-tissue tumor mass with calcifications and two osteolytic lesions with a sclerotic rim. A skeletal survey showed more osteolytic lesions, but the magnetic resonance imaging showed no more soft-tissue lesions. The rapid frozen section biopsy hinted at the diagnosis of histiocytosis X. The definitive histological result 6 days later was infantile myofibromatosis. As therapy, we determined a wait-and-see policy with controls all 3 months. At 20 months follow-up, the boy showed beginning of regression of all lesions. Infantile myofibromatosis is a very rare benign tumor-disease. Radiologically often soft-tissue masses with calcifications and osteolytic lesions with sclerotic rims are described. These findings also can be interpreted as histiocytosis X, which is a potential differential diagnosis. Histopathologically, cells characteristically appear as spindle-shaped fibroblast cells with pale pink cytoplasm and elongated nuclei and the immunophenotype is defined with a positive reaction on smooth-muscle antigen vimentin and the muscle-specific antigen HHF-35. The data of the literature review underline that a wait-and-see-policy should be considered as the first treatment of choice as in most instances the bony lesions regress spontaneously. However, a thorough examination has to be carried out to exclude lesion in other organs like gastro-intestinal or cardio-pulmonary nodular tumor masses. In conclusion, the present case report and the literature review support the notion that infantile myofibromatosis should be considered as a possible differential diagnosis for soft tissue expansions and/or osteolytic lesions in a newborn.

Solitary infantile myofibromatosis in the bones of the upper extremities: Two rare cases and a review of the literature

“…Calcifications are frequent observations and the mitotic activity is minimally increased (21). The typical IM immunohistological staining result is positive for VIM and SMA, whereas it is negative for S-100 epithelial membrane antigen and cytokeratin (22).…”

“…Although spontaneous regression is reported in a large number of cases, recurrence has also been reported (10,11). Surgical excision should be reserved for cases that affect the vital functions (21). IM with visceral involvement may require surgical or medical treatment, including radiotherapy or chemotherapy with vincristine, actinomycin D and cyclophosphamide, together with supportive care (24).…”

“…Subsequent to confirming a diagnosis, chest and abdominal imaging must be performed to evaluate the overall prognosis and to direct treatment (5). The patient should be followed up to assess recurrences and to exclude the manifestation of further nodules characterizing myofibromatosis (21). …”

Diagnosis of infantile myofibromatosis with pseudo-ulcerated plaque using prenatal ultrasound: A case report

“…The solitary form of IM usually occurs in the skin, subcutaneous tissues, muscles and the skull, with good prognosis (3,16–19). By contrast, the multicentric form of IM widely invades subcutaneous muscles, bones and viscera (1,19,20). Both solitary and multicentric forms of IM are associated with poor prognosis if they affect viscera, particularly the heart, the lungs and gastrointestinal tracts (9,13,18).…”

“…Infantile myofibromatosis (IM), a rare benign neoplasm with an incidence of 1 in 400,000 (1), can occur at any organ, particularly the skin or subcutaneous tissues or muscles (2,3). IM is the most common fibrocellular tumor in infancy and childhood (4–6).…”