Chest wall mesenchymal hamartoma in an infant: Evaluation with electrical impedance tomography.

Mesenchymal hamartoma of the chest wall is a rare benign nonneoplastic lesion of infancy arising from chondro-osseous tissue. Although its natural history suggests spontaneous regression, we describe a fatal case in a neonate with significant respiratory compromise. We explored the use of electrical impedance tomography to evaluate the dynamic impact of such space occupying lesions on a ventilated infant.

Congenital mesenchymoma of tibia: case report and review of literature.

Fibrocartilaginous mesenchymoma is a rare bone tumor arising from long bones in children and adolescents. With only 21 cases reported in the literature, it is often not included in the differential diagnosis in patients with a bone tumor. Previously, the youngest case reported was in a 19-month-old boy, and a congenital variant had not been reported. We describe a case of congenital fibrocartilaginous mesenchymoma of the proximal tibia that presented shortly after birth. Biopsy of a suspected malignancy on imaging confirmed the diagnosis. The child was temporarily lost to follow up and presented again with genu varum and limb shortening but surprisingly, the tumor had completely resolved without surgical intervention.

Primitive myxoid mesenchymal tumor of infancy: report of two cases and review of the literature.

Primitive myxoid mesenchymal tumor of infancy is a recently recognized soft tissue tumor with only a few cases reported. Here, we reported another two cases of the lesion, a 5-month-old boy presenting with a soft tissue mass in the neck region that recurred 2 months later and a 3-day-old girl with a congenital superficial dorsal lumbar mass that extended to the spinal canal 1 month later. They shared similar histological patterns, such as unusual diffuse myxoid background, delicate vascular network, small cystic spaces, low to moderate cellularity, and primitive mesenchymal tumor cells. Immunohistochemically, the tumor cells showed positive for vimentin, CD99, CD117 and nestin, negative for myoid, lipoblastic, histiocytic, and neural markers. In conclusion, primitive myxoid mesenchymal tumor of infancy is a distinctive entity with its own clinical pathological features. Expression of CD99, CD117 and nestin may be consistent with the primitive nature of the tumor and may serve as ancillary markers for differential diagnosis from the other infantile tumors.

Infantile myofibromatosis.

Infantile myofibromatosis is a mesenchymal tumor most commonly seen in infancy. The tumors have a variable appearance on CT/MR and often simulate a more aggressive neoplasm. This report describes CT/MR findings in cases of infantile myofibromatosis with pathologic correlation. Discussion into the success of imaging in suggesting the correct diagnosis is also addressed.

Ectomesenchymoma: one or two tumors? Case report and review of the literature.

Ectomesenchymoma has not previously been reported in a patient with the cutaneous nevus syndrome. A case of perineal ectomesenchymoma is presented with unusual cytogenetic findings. The significance of these is discussed and the world literature reviewed. This is the first such case reported.

Thoracic mesenchymoma of infancy.

Mesenchymoma of the chest wall is rare in infancy and can be easily mistaken for a malignant tumor. It is a distinct pathological entity that presents at birth or during infancy as self-limiting expansile intraosseous lesions involving the body of one or more ribs. Histologically, it is a benign focal overgrowth of normal skeletal elements. Two such cases are presented.

A case of cerebellar neuroectomesenchymoma in an infant.

This case report concerns a congenital cerebellar tumor in an infant. The tumor consisted of small, immature lymphocyte-like cells, medium-sized, rhabdoid cell-like cells, and large, polymorphic gemistocytic astrocyte-like cells, which were admixed in motley form on a background of neuronal matrix and dural and collagen fibrous tissues. Immunohistochemical studies revealed that the cytoplasm of rhabdoid cells had conspicuous structures, resembling weakly eosinophilic homogeneously amorphous inclusion bodies, and that the strongly eosinophilic cytoplasm, seen abundantly in the gemistocytic astrocyte-like cells, was a mixture of components that were positive for glial fibrillary acidic protein (GFAP) and vimentin and of components positive for myoglobin. Because of the simultaneous expression of both, neuroectodermal and mesenchymal characteristics the reported tumor was not a mixed tumor of independent neuroectodermal and mesenchymal tumor components, but a very rare neuroectomesenchymoma derived from immature cells with pluripotential differentiating capabilities.

Polyphenotypic small-cell orbitocranial tumor.

A male infant was born with a massive orbitocranial tumor without evidence of metastasis. On light microscopy, the histologic pattern of the tumor was that of a largely necrotic and highly undifferentiated small round cell neoplasm of uncertain origin. Ultrastructural features of the primitive cells included a rare tight junction and myofibril. Immunohistochemical studies showed positive staining for cytokeratin, vimentin, muscle-specific actin, neuron-specific enolase, and S100 protein and negativity for desmin and leukocyte common antigen. We believe this case represents an example of a polyphenotypic small-cell tumor of childhood with epithelial, rhabdomyoblastic, and neuroectodermal differentiation.

Congenital benign mesenchymoma of the head and neck.

Congenital benign mesenchymoma of the head and neck is rare. One such case, presenting as a mass in the neck, is reported and the literature reviewed. Pathologic nature of the lesion is discussed. Prognosis after adequate local excision is good.

Congenital osteolipoma of the skull.

A unique case of congenital osteolipoma of the skull occurred. A 27-year-old woman had multiple hard tumors affecting the frontal and parietal bones, the rim of the orbit, the maxilla, the base of the skull, and the horizontal part of the mandible on the right side. The slowly growing tumor was first noticed in the right parietal bone when she was born. The partially excised right frontoparietal lesion was composed of deformed and sclerotic trabeculae of bone and mature adipose tissue that formed an osteolipoma, which was regarded as hamartomatous. Its pathogenesis was suggested as associated with maldifferentiation of the mesenchyme or its derivatives toward the osseous and adipose tissue at the early development of the cranium.

Dystocia, consumptive coagulopathy, and cardiac failure as complications of a congenital benign mesenchymoma.

A congenital benign mesenchymoma which arose in the right foot resulted in dystocia. Shortly after birth, high-output cardiac failure developed secondary to abnormal shunting in the extensive irregular vasculature. Consumptive coagulopathy also occurred, believed to be the result of widely dilated abnormal vessels and extensive necrosis secondary to the trauma of the dystocia. These problems disappeared after resection of the tumor; there has been no recurrence after 2 years.

Hamartoma (mesenchymoma) of the chest wall in infancy.

Chest wall hamartoma, commonly known as mesenchymoma, is very rare in infants and usually present at birth. This lesion is a focal overgrowth of normal skeletal elements, Histologically, it is benign. The radiographic appearance is that of a partially mineralized extrapleural mass involving one or more ribs. Surgical ablation seems to be the proper treatment and is curative. Nine cases of this condition are presented, including long-term follow-up in 4.

Occipital mesenchymal tumors of infancy. Report of three cases.

Mesenchymal tumors arising from the dura in three newborn babies are described, with discussion of their clinical and pathological significance.