Congenital myofibroma.A true hemangiopericytoma.

A neonatal case with immunohistochemical and

ultrastructural studies.Ezequiel Trejo-Scorza

Alipio Antonio Hernández-Faraco Jesùs Marìa Alvarado-Sanavria

Maternidad “Concepciòn Palacios”República de Venezuela

Introduction Malignant tumors in the newborn are rare. Mejia-

Aranguré (1) found only 74 cases in a series of 4595 cases. (2005)

In newborns, the most common solid tumors are: Neuroblastoma Teratomas Soft tissue tumors

The most common soft tissue tumors are: Myofibroma / myofibromatosis Fibrosarcoma Rhabdomyosarcomas

The most common fibroblasts and myofibroblasts tumors are: Myofibroma / myofibromatosis (benign) Fibrosarcoma (malignant)

Myofibroma single or multiple Single or multiple lesions Stout and Murray (1942): endothelium-lined ducts

surrounded by packets of round cells that show a tendency to differentiate into myofibroblasts, which called hemangiopericytoma, and derived from pericytes.

Case report RN born male, with

appropriate weight for gestational age, obtained by vaginal delivery in primiparous mother of 19 year-old.

Physical examination evidence, oval tumor 3 x 2 x 2 cm in right malar region, with a pedicle of 0.5 cm midway between the two extremes.

The surface of the pedicle contralateral tumor present area of purple, the next day becomes necrotic.

The rest of the surface was pink, well vascularized.

Diagnostic tests A CT scan revealed a tumor

of dermal origin, with the deeper layers and bone, free of infiltration.

Doppler sonogram shows low vascularity of tumor, except at the pedicle where blood flow was found.

Surgery performed

At the 4 th day of life, total excision of the lesion. Buttonhole incision around the tumor pedicle to the outer face of the right zygomatic bone.

The patient was discharged at 10º days of life with successful postoperative outcome.

Histopathology The conventional histological

examination showed tumor located in the dermis with solid nodules, isolated and confluent, expansive edge compared to normal tissue surrounding country.

It showed foci of intratumoral necrosis

Histopathology And endovascular

subendothelial growth of the tumor into dilated venules and lymphatic vessels of the dermis.

The neoplasm is characterized by a nodular proliferation with a biphasic pattern composed of round cells and spindle

Round cells were located in the central region of the lymph vascular small slits arranged between collapsed and covered with normal endothelium.(A)

The spindle cells were located in the periphery and had a look smooth muscle with blunt-ended elongated nuclei and fibrillary eosinophilic cytoplasm aspect. (B)

All tumor cells (spindle or round) exhibited strong reaction to PAS pericellular.

Immunohistochemistry Table No. 1

Results of immunoreaction Immunoreactions Results (neoplastic cells)

CD34 and vimentin Diffuse cytoplasmic positivity for spindle cell component, and for least differentiated tumor cells

Alpha smooth muscle actin Cytoplasmic positivity for spindle cell component, and less differentiated tumor cells isolated

PGP 9.5 and S100 protein Nuclear positivity for malignant cells isolated

Desmin, Factor VIII and Epstein-Barr Negative for tumor

Immunoreactions Tumor diffuse

immunopositivity for CD34. In (A) the immune response of endothelial cells to CD34 shows subendothelial tumor growth.

In (B) focal immunopositivity in peripheral spindle cells for smooth muscle actin.

Ultrastructural study Basement membrane lining

(*) Numerous cytoplasmic

intermediate filaments with dense body formation (smooth muscle differentiation) (O)

Discussion

Discussion The myofibroma is a tumor arising from pericytes and

its cells undergoing myofibroblastic differentiation Myofibroma presented the clinical, histopathological

and prognostic allowing differentiate solitary fibrous tumor and hemangiopericytoma injuries, findings reveal "hemangiopericytoma-like"

Clinic In childhood is the most common fibromatosis 90% of cases are diagnosed by 1 year of age Predilection for males It can occur alone (myofibroma) or multiple

(myofibromatosis) Single lesions are confined to the skin, subcutaneous

tissue or skeletal muscle of the head, neck or trunk When surface have the appearance of purplish spots and

doppler ecosonography allows to differentiate hemangiomas

When lesions are multiple runs with 25% damage and visceral organs most commonly affected are heart, lung and gastrointestinal tract.

Clinical prognosis

The clinical outcome will depend on the location of the tumor and the number of organs involved: Solitary visceral myofibroma Myofibromatosis with single

visceral involvement Myofibromatosis with

multiple visceral involvement

Differential Diagnosis With lesions deployed

findings "hemangiopericytoma-like“ Congenital fibrosarcoma, Solitary fibrous tumor.

Conclusion The myofibroma is a tumor that may be present at birth When the lesions are superficial and have the appearance of

purplish spots ecosonography doppler allows to differentiate hemangiomas

The immunohistochemistry and electron microscopy show clear evidence of myofibroblastic differentiation of the periendoteliales tumor cells and therefore are hemangiopericytomas true, because we propose the term “myofibropericitoma", to emphasize its pericitic origin and myofibroblastic differentiation.

True hemangiopericytomas Sinonasal-type

hemangiopericytoma with myoid differentiation

Myofibromas (myofibropericytoma)

Glomangiopericytoma Myopericytoma