Rapid spontaneous regression of multicentric infantile myofibromatosis in the posterior fossa and lumbar vertebra

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.

Giant intracranial infantile myofibromatosis of the skull base: report of two cases

Infantile myofibromatosis is a rare and nonmalignant pediatric tumor of myofibroblastic origin that may occur in solitary or multifocal forms. Soft tissue of the head and neck, trunk, and extremities, skeleton, and viscera are usually involved. Intracranial involvement is reported to be extremely rare, and its clinical picture has been poorly characterized. We present two cases of giant infantile myofibromatosis of the skull base with intracranial involvement. The first case with prenatal diagnosis involved extensively the extradural space of the occipital region and was previously treated by chemotherapy for a previous diagnosis of hemangioperycitoma. Tumor was removed at the age of 5 months and no recurrence was observed during the 3-year follow-up. The second case in a 2-year-old baby involved the anterior cranial base, the nasal cavity, the right orbit, and presented massive involvement of the anterior cranial fossa. Surgery allowed complete removal and a recurrence-free period of 7 years after surgery. Treatment options for these unusual cases are presented and details of histological diagnosis are discussed.

Mesenchymal Neoplasms of Salivary Glands: A Clinicopathologic Study of 68 Cases

Salivary gland neoplasms are uncommon, and most exhibit epithelial differentiation. Mesenchymal neoplasms of the salivary gland are rare, and the incidence ranges from 1.9% to 5%. The aim of this study is to identify the types and clinical-pathological features of mesenchymal salivary neoplasm and review their differential diagnosis. A retrospective search for mesenchymal neoplasms of salivary glands from our institution's pathology archives from the 2004-2021 period and consultation files of one of the authors (AER) was performed. The clinical data were obtained from available medical records, and the histological slides and ancillary studies were retrieved and reviewed. We identified a total of 68 cases that form the study cohort. Thirty-five patients were male, and thirty-three patients were female, with a mean age of 48 years (range, 7 months-79 years), and the male to female ratio was 1:.94. Sixty-three (92.6%) of sixty-eight tumors were benign and included: 38 (56%) lipomas, 9 (13%) hemangiomas, 7 (10.3%) schwannomas, 3 (4.4%) neurofibromas, 3 (4.4%) lymphangioma, 2 (3%) solitary fibrous tumors, 1 (1.5%) myofibroma. Five of sixty-eight (7.4%) were malignant and included: 3 (4.4%) Adamantinoma-like Ewing sarcomas, 1 (1.5%) malignant peripheral nerve sheath tumor (MPNST), and 1 (1.5%) malignant solitary fibrous tumor. The involved sites included: parotid (55), submandibular gland (5), parapharyngeal space (5), buccal mucosa minor salivary gland (2), and sublingual gland (1). Sixty-seven patients underwent surgical resection. One patient with lymphangioma manifested a recurrence/persistence a week post-surgery. One patient with a parotid hemangioma developed post-operative numbness, and another patient developed chronic postauricular pain after surgery. Two patients with MPNST and one patient with adamantinoma-like Ewing sarcoma underwent neoadjuvant chemoradiation and were disease-free after treatment. The remaining 37 patients with available follow-up ranging from 7 days to 96 months (mean, 18 months) had a favorable outcome and were disease-free after treatment. Mesenchymal neoplasms of salivary gland are rare; most are benign and demonstrate adipocytic, endothelial, and schwannian differentiation; awareness of their development is important for adequate diagnosis. The mainstay of treatment is surgical excision, with the extent determined by tumor type. Adjuvant therapy is reserved for high-grade sarcomas and may be given in a neoadjuvant or adjuvant setting.

Solitary myofibroma of the lumbar vertebra in young adult: A case report with 4-year follow-up of postoperative CT or MRI

BACKGROUND

Solitary myofibroma of the spine is extremely rare, particularly among adults. To the best of our knowledge, only 3 cases affecting lumbar vertebrae have been reported in the English language literature. Of them, only 1 case was an adult case of solitary myofibroma affecting the L1 vertebra.

METHODS

We report a case of solitary myofibroma affecting the L5 vertebra in an 18-year-old man and the postoperative imaging of solitary myofibroma for the first time. Conventional radiographs demonstrated an expansile osteolytic lesion with thinned cortex and marginal sclerosis. Computed tomography (CT) showed a purely osteolytic expansile lesion with partial disappearance of thinned cortex. MRI of the lesion revealed an isointense signal on T1-weighted images, an inhomogeneous slightly hyperintense signal on T2-weighed images, and homogeneous avid enhancement with gadolinium.

RESULTS

Surgical excision was performed and the lesion was diagnosed as solitary myofibroma on pathological examination. One-year follow-up postoperative CT demonstrated decreased size of the osteolytic lesion with sclerotic change. Four-year follow-up postoperative MRI revealed complete resolution of the lesion replaced by normal fatty marrow.

CONCLUSION

If a benign-looking expansile osteolytic lesion reveals a homogeneously isointense signal on T1-weighted image, inhomogeneous slightly hyperintense signal on T2-weighted image, and homogeneous avid enhancement with gadolinium, solitary myofibroma should be considered in the differential diagnosis of spine bone tumors. It can be resolved completely.

Infantile myofibromatosis of the iliac bone

INTRODUCTION

Solitary infantile myofibromatosis (IM) of bone is a rare benign osseous tumor of childhood with low rate of recurrence. Well documented within the multicenter form, its solitary intraosseous location is less well described.

CASE REPORT

We present a rare case of intraosseous myofibromatosis arising the iliac bone of a 11-year-old girl, who was operated at 2 months of life for a retroauricular subcutaneous MF with unbalanced translocation t(9;16). She presented with a limping associated to a stiffness of the hip without pain. Imaging disclosed a 4×4×1cm intraosseous, lytic and heterogeneous mass with a soft tissue component on the medial cortical of the left iliac bone. Open biopsy was performed. Histology revealed proliferation of fusiform cells with eosinophil cytoplasm embedded in a myxoid and fibrous stroma without mitotic figures. On immunohistochemistry, cells were positive for actin, PS100, KL1, focally positive for EMA, CD34, P63, rarely CD31, which indicated diagnosis of new localization of IM. Cytogenetic analysis revealed absence of translocation t(9;16), which was found in the first tumor. Subsequent total resection was performed. The patient recovered normal function without recurrence of tumor at 3 years follow-up.

CONCLUSION

To our knowledge, this is the first case of solitary IM of the iliac bone, occurring 12 years after the first localization. Total resection resulted in excellent outcome. However recurrence can happen even long time after the first resection and new localization is possible, as in our case. This suggests close follow-up and clear information about the risk of recurrence.

Ruptured Infantile Myofibroma of the Head Presenting in a Neonate: Case Report and Review of the Literature

BACKGROUND

Infantile myofibroma/myofibromatosis (IM/M) is a myofibroblastic proliferative disorder often seen in infants and children. IM/M can result in congenital tumors of the head and neck and may occasionally present to the neurosurgeon.

CASE DESCRIPTION

We report a case of a solitary ruptured myofibroma of the head in a newborn patient. The lesion was initially suggestive of encephalocele. We describe the presentation and management of this patient, including relevant imaging, histopathologic evaluation, and surgical technique. We subsequently review the literature of IM/M of the head and neck, highlighting the 3 forms of the condition, each requiring a distinct management strategy.

CONCLUSIONS

Although this tumor rarely presents to the neurosurgeon, it may do so in the process of ruling out other more dangerous conditions. It is therefore important to consider this diagnosis in masses that occur in the head and neck of newborns.