Metastatic peripheral primitive neuroectodermal tumor (PNET) masquerading as liver abscess: a case report of liver metastasis in orbital PNET

A case report of neonatal orbital peripheral primitive neuroectodermal tumor and literature review

Primitive neuroectodermal tumors are rare malignant neoplasms from primitive neural crest cells. Most primitive neuroectodermal tumors occur in the central and sympathetic nervous systems. We report a Chinese newborn patient presenting a huge unilateral proptosis after birth, diagnosed as orbital peripheral primitive neuroectodermal tumor by histopathology and immunohistochemistry. Our case is the first reported case of orbital peripheral primitive neuroectodermal tumor diagnosed in the newborn period. The clinical manifestations, radiological findings, histopathologic, and immunohistochemistry results are described in detail. We also conducted a literature search focusing on primitive neuroectodermal tumor of the orbit. To the best of our knowledge, all articles with English abstracts were reviewed here.

Pediatric Orbital Primitive Neuroectodermal Tumors

PURPOSE

To present the clinical, radiological, histopathological, immunohistochemical features and the follow-up of orbital primitive neuroectodermal tumors (PNETs) in pediatric patients along with a review of the literature.

METHODS

A retrospective analysis of all diagnosed cases of orbital PNET was done. Patients' ophthalmic findings, imaging, immunohistochemistry, metastatic work-up, treatment, globe salvation, and survival were documented and a mini literature review of orbital PNET was performed.

RESULTS

Four diagnosed cases of orbital PNET presented with proptosis and visual impairment were treated during the study period. The radiological imaging showed primary orbital involvement. There were three males and one female with a mean age of 63.75 months (range: 3 to 244 months). Histopathology of all studied patients showed round malignant cells with hyperchromatic nuclei, increased nuclear cytoplasmic ratio, and positive test results for CD99 and FLI-1. The studied patients underwent orbital surgery for excision of tumors followed by chemotherapy. One of the patients also had external radiation in addition to chemotherapy after a second recurrence. The follow-up period of these patients varied from 1 to 5 years. Only one child who had recurrence twice was followed up to 5 years, but was lost to follow-up after that.

CONCLUSIONS

The authors believe that most orbital peripheral PNET tumors present as well-defined masses on both imaging and perioperatively and are easily removed surgically. The apparently disguised "benign profile" of orbital PNET may prove deceptive and the shorter duration of symptoms remains a strong reminder of the malignant nature of the lesion. [J Pediatr Ophthalmol Strabismus. 2018;55(2):93-99.].

Primary orbital Ewing sarcoma

The authors report the clinical manifestations, pathologic character, management, and prognosis of primary orbital Ewing sarcoma, and review pertinent literature. A 6-year-old boy presented with the complaint of abruptly decreasing visual acuity and right proptosis. Computed tomography scan revealed a mass in the region of the right infratemporal orbit with extension into the infratemporal fossa and masseteric space, and there was erosion of the right lateral orbital wall. An anterior orbitotomy eyelid crease was performed to remove the tumor. The tumor cells were positive in membranous pattern for CD99 immunostaining; all other reactions were negative. The EWS-FLI-1 fusion gene was not detected by reverse-transcription polymerase chain reaction. Combined radiotherapy was applied. Primary orbital Ewing sarcoma is an extremely rare malignant tumor that shows a predilection for males (ratio: 1.4 to 1). Appropriate treatment consists of local resection, radiotherapy, and adjunctive chemotherapy.

Primitive neuroectodermal tumor of the liver: a case report

Ewing sarcoma/primitive neuroectodermal tumor is a rare tumor of soft tissues of thoraco-pulmonary regions, pelvis and lower extremities. Involvement of visceral organs by primitive neuroectodermal tumor is even rarer, with the kidney being the most commonly involved organ. Involvement of the liver has been reported in the form of metastasis from other primary sources presenting as liver abscess. We report a 20-year-old lady presenting with massive hepatomegaly, with computed tomography scan evidence of diffuse hepatomegaly and a normal porta and intrahepatic biliary radicles. She subsequently underwent ultrasonography-guided true-cut needle biopsy of the liver. Histopathology of the liver revealed nests of small round blue tumor cells in the background of hepatocytes infiltrating the liver, which expressed Mic-2 and Fli-1, and were negative for cytokeratin, desmin, hepatocyte-specific antigen (OCHIE5), synaptophysin, chromogranin A and CD-20. Immunohistochemistry revealed CD-99-positive. Extensive search regarding any possible different site of involvement by the tumor was negative. The patient responded to a combination therapy of vincristine, adriamycin and cyclophosphamide alternating with ifosfamide and etoposide 3 weekly over 43 weeks and has been doing well even after 1 year of diagnosis. The clinical presentation, the macroscopic aspect, together with the histological pattern, the cytological characteristic and the cellular immunophenotype lead to the diagnosis of primary primitive neuroectodermal tumor of the liver which responded well to combination chemotherapy.

Ewing sarcoma presenting as a subconjunctival mass

A 14-year-old previously healthy boy presented for evaluation of a subconjunctival mass that had been present for 2 to 3 years, but had recently started to enlarge. Imaging demonstrated an anterior orbital lesion that enhanced with gadolinium. An excisional biopsy was performed and revealed highly malignant-appearing small, blue, round tumor cells. Immuohistochemical stains were strongly reactive with CD99 (MIC2 and O13), CD56, and retained INI-1 reactivity. The EWS-FLI1 chimeric fusion gene transcript was also detected by reverse transcription-polymerase chain reaction analysis, confirming Ewing sarcoma. Full-body CT, bone scan, and bone marrow biopsy were all negative, proving this to be a premetastatic, primary orbital tumor arising from soft tissue.

Tumeur neuro-ectodermique primitive orbitaire avec extension endocrânienne

Primitive neuroectodermal tumor (PNET) of the orbit is rare. We present a case of a young patient with orbital PNET extending to the endo-crane and sinuses, which had been treated 10 years before with the diagnosis of rhabdomyosarcoma. The diagnosis was corrected with immunohistochemistry. Through this observation, we discuss the clinical aspects, the diagnosis difficulties, and the therapeutic options of this rare affection.

Mouth metastasis of peripheral primitive neuroectodermal tumor

We describe a case of oral metastasis of peripheral primitive neuroectodermal tumor (pPNET) in a 68-year-old man, who presented the primary lesion in the chest. Oral metastasis of pPNETs is very rare and we have not found any similar case reported in the English literature. Clinical examination showed an extensive and ulcerated fleshy mass measuring 3.0 x 3.5 cm in the right lower gingivae. Microscopic examination showed sheets of proliferating small, hyperchromatic, round cells. Tumor cells were reactive to neuron-specific enolase (NSE), vimentin and MIC-2 gene by immunohistochemistry, consistent with PNET. The patient died 3 weeks later because of respiratory insufficiency.