Solitary form of infantile myofibromatosis: a histologic, immunohistochemical, and electronmicroscopic study of a regressing tumor over a 20-month period

A misleading tumor: A rare form of infantile fibromatosis

Infantile fibromatosis is a rare mesenchymal disorder characterized by the fibrous proliferation of the skin, bone, muscle, and viscera. The clinical features vary from solitary to multicentric forms with similar pathological features. Although the tumor is histologically benign, it is a highly infiltrating lesion making the prognosis poor for patients with craniofacial involvement affection due to the major risk of nerve vascular and airway compression syndrome. The solitary form of infantile fibromatosis observed in the dermis, subcutis, or fibromatosis tends to occur predominantly in males and typically affects craniofacial deep soft tissues. We present a case of an unusual symptom presentation and a rarely observed location of a solitary fibromatosis form, affecting the muscle of the forearm and infiltrating the bone in a 12-year-old girl. Imaging findings were suggestive of rhabdomyosarcoma, but histopathology set the diagnosis of an infantile fibromatosis. The patient, then, received chemotherapy, and amputation was proposed due to the inextricability of this benign yet aggressive tumor, an option that was refused by her parents. We discuss through this article the clinical, radiological, and pathological features of this benign yet aggressive condition, the potential differential diagnosis, the prognosis, and treatment options substantiated with concrete examples from the literature.

Prenatal diagnosis of infantile myofibromatosis of the lung: a case report and review of the literature

We present a case of infantile myofibromatosis of the lung detected at 32 weeks' gestation. The fetus was monitored with weekly ultrasound examinations measuring the mass size and amniotic fluid index. On day 2 after delivery, due to respiratory distress, an exploratory thoracotomy was undertaken and the mass was resected.

Congenital myofibroma of the skin mimicking a piloleiomyoma

Myofibroma is an uncommon benign soft tissue disorder, which is usually congenital or present in early infancy. Myofibroma usually manifests as a single mass. When there are multiple lesions, the term myofibromatosis is used. The characteristic histopathological feature of the myofibroma is the coexistence of two distinct areas. One area mainly contains plump spindle cells with thin blunt-ended nuclei and eosinophilic cytoplasm, thus indicating myoid characteristics. The other area contains either round or polygonal cells with slightly pleomorphic, hyperchromatic nuclei or small spindle cells typically arranged around a distinct hemangiopericytoma-like vascular pattern. In the present case, the majority of the tumor was composed of the plump myoid spindle cells. This led to an initial diagnosis of a piloleiomyoma. However, the tumor cells were not immunohistochemically positive for desmin. Moreover, careful examination revealed a hemangiopericytoma-like vascular pattern characterized by the presence of high cellular areas with irregular vascular spaces. These features led to the final diagnosis of the myofibroma. It is therefore important to recognize the leiomyoma-like variants of myofibromas.

Myofibroblastic sarcoma of the nasal cavity and paranasal sinus: a clinicopathologic study of 6 cases and review of the literature

OBJECTIVE

We describe the clinicopathologic features of 6 cases of myofibroblastic sarcoma (MS) occurring in the nasal cavity and paranasal sinus.

STUDY DESIGN

The paraffin-embedded tissues of 6 cases of MS were stained immunohistochemically and examined by electron microscopy.

RESULTS

Clinically, a painless enlarging mass was the most common symptom, followed by the nasal obstruction, epistaxis, copious rhinorrhea, and proptosis. Histologically, the tumors showed a diffusely infiltrative growth pattern and consisted mainly of spindle cells with abundant eosinophilic cytoplasm. The hypocellular myxoid areas and the hypercellular fibrous areas were identified. Immunohistochemically, all 6 tumors were positive for vimentin, alpha-smooth muscle actin, calponin, and fibronectin. Ultrastructural examination in 3 cases showed characteristic features of myofibroblast. Follow-up in 6 patients revealed high local recurrence rate (6 out of 6).

CONCLUSION

Myofibroblastic sarcoma of the nasal cavity and paranasal sinus exhibit diverse histologic appearances and a strong aggressive behavior.

Solitary myofibroma of the sclera

PURPOSE

To report a novel case of solitary myofibroma involving the sclera.

METHODS

Case report and review of the literature.

RESULTS

A 19-year-old woman had an expanding and painful epibulbar mass clinically diagnosed as nodular scleritis that did not respond to anti-inflammatory therapy. A biopsy showed a proliferation of spindle-shaped cells that reacted strongly positively with immunoperoxidase stains for vimentin and smooth-muscle actin. The diagnosis of solitary myofibroma was made. Six months postoperatively, the patient was well, and the lesion had not recurred.

CONCLUSIONS

Myofibroma should be considered in the differential diagnosis of an epibulbar mass, especially in the setting that would mimic nodular scleritis.

Myofibromatose infantile cutanée isolée

Infantile myofibromatosis is the most frequent fibromatosis in childhood. It is a benign proliferation of fibroblasts and myofibroblasts. This case report concerns a newborn who presented at birth with a purple cutaneous nodule on the scalp. Surgical excision was performed at the age of 16 months. Infantile myofibromatosis was diagnosed on histology. Infantile Myofibromatosis (IMF) was first described by Enzinger in 1981. Three types can exist. Solitary MFI, the most frequent, is a solitary lesion, cutaneous/subcutaneous, osseous or involving soft tissues. Multicentric disease is characterized by multiple locations and generalized form by visceral involvement. Morphological features are identical in all types. The histological diagnosis relies on the identification of two separate components, a fascicular myofibroblastic pattern at the periphery with a hemangiopericytoma like pattern in the centre. Both components are positive for alpha-smooth muscle actin. Atypia, or mitotic activity, are not observed usually but features of intravascular growth can be seen in the centre of the lesion. Infantile MF carries a good prognosis when solitary but death frequently occurs in generalized MF with visceral involvement.

Autosomal dominant inheritance of infantile myofibromatosis

We present three families with infantile myofibromatosis (IM; OMIM no. 228550) inherited in an autosomal dominant (AD) manner. These three pedigrees prompted re-assessment of pedigrees available within the genetic, oncologic, surgical, and pathologic literature, which suggest autosomal recessive (AR) inheritance. All familial IM may be interpreted as AD or, alternatively, there may be genetic heterogeneity for IM. As most nodules tend to regress spontaneously, familial history may be difficult to obtain and/or confirm. Clinical diagnosis and establishment of inheritance pattern can be important for prognosis and the recognition that other family members may be affected.

Infantile myofibromatosis with visceral involvement and complete spontaneous regression

Infantile myofibromatosis is an unusual mesenchymal disorder characterized by the proliferation of tumors in the skin, muscle, bone, and viscera. 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. 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. On the other hand, 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. The case being reported here, is that of a female newborn who had multiple skin, subcutaneous tissue, skeletal muscle, bone, and lung lesions immediately after bith. At the age of three years, the child is in good health, her psychomotor development is in accordance with her age group, and the lesions have completely regressed. This is a case of the multicentic type of infantile myofibromatosis with visceral involvement, where all lesions have spontaneously regressed. This is a rarity since the prognosis in the majority of such cases is poor.

Infantile myofibromatosis: case report of a solitary hand lesion with emphasis on differential diagnosis and management

Infantile myofibromatosis, both solitary and multicentric types, is discussed with emphasis on the importance of diagnosing this condition correctly. Its distinctive clinical and histological characteristics are described, as are the hazards of overhasty and overly ambitious surgical intervention. Other similarly presenting fibromatous diseases of infancy and childhood are discussed, including aplasia cutis, infantile fibrosarcoma, recurring infantile digital fibromatosis, and juvenile aponeurotic fibromatosis. A case of infantile myofibromatosis, solitary type, is reported, and the two surgical procedures carried out over a 4-year period are described. The importance of histological and immunohistochemical evaluation of lesions present during the neonatal period is stressed.