Ectopic intrapelvic medulloepithelioma: case Report

Abstract

A primary extraspinal medulloepithelioma with lung metastases is reported. The tumour was located in the presacral area. Microscopically, it showed typical features of medulloepithelioma with focal ependymal differentiation. Medulloepitheliomas are malignant tumours of primitive neuro-epithelium usually involving the cerebral hemispheres. This report demonstrates their possible extraspinal presacral occurrence. By immunohistochemistry, neuron-specific-enolase, S100 protein, vimentin, cytokeratin and glial fibrillary acidic protein were found in some tumour cells. Electron microscopy demonstrated poorly differentiated cells forming stratified epithelium resting on a basal lamina and short junctional complexes at the apical pole. Ultrastructural evidence of ependymal differentiation was observed. Presacral medulloepithelioma may arise from undifferentiated embryonic cells forming the presacral remnants of the neurenteric canal.

Presacral Medulloepithelioma—de Novo or Teratomatous?

“…Outside the central nervous system and eye, medulloepitheliomas may represent the malignant neural component of a teratoma. Least commonly, de novo medulloepitheliomas may arise peripherally, so far reported only in the presacral region [3,4], pelvis [1], or along the sciatic nerve [5]. Although in these tumors the medulloepitheliomatous pattern is predominant, other neural elements are routinely found to lesser and more variable degrees.…”

“…Peripherally, medulloepitheliomas may be a component of a malignant teratoma, or more rarely, as a primitive neuroectodermal tumor histologically distinct from Ewing's sarcoma. Two presacral medulloepithelioma's have been described [3,4], both have been localized at presentation. We report a medulloepithelioma presenting as a presacral mass with multiple liver and a solitary lung metastases.…”

Peripheral medulloepithelioma: a rare tumor with a potential target therapy

“…All reported PME were located in the pelvic cavity (Table 2). Some authors hypothesized that these tumors originated from undifferentiated cells of the pre-sacral remnant [6]. Four patients with ovarian ME had a good prognosis after surgery either alone or associated with adjuvant chemotherapy and/or radiotherapy [5].…”

“…In a case of congenital pelvic ME, prolonged disease-free survival was achieved after partial surgical removal and chemotherapy [7]. In a similar case, pelvic ME was resistant to chemotherapy and the patient died of metastatic pulmonary progression [6]. …”

Presacral Medulloepithelioma—De Novo or Teratomatous?

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Medulloepitheliomas are rare, childhood embryonal multipotential neuroepithelial tumors [1] involving either central nervous system (cerebrum, cerebellum, spinal cord) or the ciliary body of the eye. Two presacral medulloepithelioma's have been described [3,4], both have been localized at presentation. Peripherally, medulloepitheliomas may be a component of a malignant teratoma, or more rarely, as a primitive neuroectodermal tumor histologically distinct from Ewing's sarcoma.

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