|Year : 2016 | Volume
| Issue : 2 | Page : 81-83
Primary pleural primitive neuroendocrine tumor: A rare entity
Mayuri Johari, Deepak Kumar Prajapat, Arjun Khanna, Deepak Talwar
Metro Center for Respiratory Diseases, Metro Multispeciality Hospital, Noida, Uttar Pradesh, India
|Date of Web Publication||10-Jun-2016|
Metro Center for Respiratory Diseases, Metro Multispeciality Hospital, Sector 11, Noida, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
The rare primitive neuro-ectodermal tumors (PNET) are classically described as tumors of the airways that can metastasize to the pleura. We describe here, a rare case of a PNET originating from the pleura in a 52-year-old, nonsmoker female. The patient presented with clinical features of a right sided pleural effusion. Thoracoscopic pleural biopsy revealed malignant small round cell proliferation consistent with PNET, and the final diagnosis was confirmed by immune-histochemical analysis. Fiberoptic bronchoscopy, contrast enhanced computed tomography chest, and positron emission tomography scan did not reveal any primary lung lesion. The patient underwent pleurodesis for symptom relief but refused any definitive therapy.
Keywords: Malignant pleural effusion, primary pleural tumor, primitive neuro-endocrine tumor
|How to cite this article:|
Johari M, Prajapat DK, Khanna A, Talwar D. Primary pleural primitive neuroendocrine tumor: A rare entity. J Assoc Chest Physicians 2016;4:81-3
| Introduction|| |
Primitive neuro-ectodermal tumors (PNET), are rare lung tumors, usually encountered in the pediatric age group. The exact etiology of these tumors is unknown and they usually arise in the peri hilar area. The condition is exceedingly rare in adults and tends to occur in young females. Primary pulmonary PNET, are postulated to arise from Kulchitsky's cells of the bronchial mucosa. Frequently, this entity appears as a chest wall mass, with rapid growth that may erode the pleura. Primary pleural PNET is an extremely rare disease entity. We herein, report a case of PNET in an adult patient primarily involving the pleural space.
| Case Report|| |
A 52-year-old nonsmoker, previously healthy female presented to us with sub-acute progressive shortness of breath, dry, and right sided pleuritic chest pain for the past 1 month. General examination revealed an average built female with insignificant findings. Examination of the respiratory system revealed absent breath sounds in right infra-mammary, infra-axillary and infra-scapular areas. Chest skiagram showed right sided moderate effusion. Routine blood investigational findings were normal. The patient underwent removal of around 1500 ml of pleural fluid at a peripheral hospital, which revealed a polymorphic, exudative effusion with mesothelial cells and a few atypical cells. Contrast enhanced computed tomography (CT) scan of the chest revealed a moderate right pleural effusion with pleural nodules, contralateral mediastinal shift, and no mediastinal lymphadenopathy. The patient was referred to our center for further management and underwent medical thoracoscopy with plueral biopsy. Gross examination of the pleura revealed multiple lobulated pleural nodules of varying sizes with no visible nodules on the lung. The cytospin examination of pleural fluid revealed a few atypical cell clusters with hyperchromatic nuclei suggestive of malignant cells. Fiberoptic bronchoscopy revealed normal bronchial anatomy. No intrabronchial mass lesion or mucosal abnormality was observed. The patient underwent a positron emission tomography (PET) CT for disease staging which revealed, a heterogeneously enhancing lesion (2.8 cm × 2.0 cm) with increased fluoro-D-glucose (FDG) uptake (maximum standardized uptake value [SUVmax]-14.6) in right pleura with multiple enhancing nodular lesions in the right pleural space with increased FDG uptake (SUVmax-7.2) involving costal and diaphragmatic pleura and increased FDG uptake in sub carinal and right lower para tracheal lymph node stations [Figure 1]. Histopathology of the Pleural biopsy revealed small round cell proliferation with mitosis of 1–2/high power field. Immuno-histochemical (IHC) findings revealed positivity for neuron specific enolase (NSE), CD-56, CD-99, S-100 and Ki-67 of 70% consistent with PNET [Figure 2].
|Figure 1: Fluoro-D-glucose positron emission tomography image showing the fluoro-D-glucose avid right sided pleural effusion|
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|Figure 2: Immuno-histochemistry panel establishing the diagnosis of pleural primitive neuro-ectodermal tumors|
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Postthoracoscopy and ICD tube placement, pleurodesis with Talc was done and ICD tube removed after 2 days. The patient's condition was discussed in the tumor board and planned palliative chemotherapy. This was refused by the patient and the attendants. The patient was lost to follow-up.
| Discussion|| |
PNET are rare tumors occurring in the posterior sulcus or chest wall of adolescent or young adult patients. Usually painful, these invasive thoracic tumors may develop on and invade chest wall, lung, or mediastinum., Radiologically, these tumors are difficult to differentiate from other thoracic neoplasms. PNETs most frequently arise from the soft tissues and the bones, but rarely have been reported in other sites, such as ovary, uterus, testis, kidney, and pancreas. In our patient, the PET-CT showed no FDG uptake in other areas except the pleura, the diagnosis of primary pleural PNET was considered. The histo-pathological differential diagnosis of PNET of the lung includes small cell carcinoma and other small round-cell tumors, such as malignant lymphoma, Langerhans' cell histiocytosis, granulocytic sarcoma, rhabdomyosarcoma, neuroblastoma, and synovial sarcoma  with the characteristic pathology of nests of small cells and Homer-Wright pseudo-rosettes with an acidophilic positivity of neurofibrillar elements. The pleural biopsy in our patient showed infiltration with round and spindle-shaped tumor cells. The differential diagnosis based on this picture included metastatic carcinoma, sarcoma, and a mesothelioma. However, CK7, thyroid transcription factor, p63, CALRETININ, HBME1 markers were negative on IHC, which ruled out adeno carcinoma and sarcomatoid mesothelioma. Further, Vimentin and CD-99 were positive, so, a diagnosis of sarcoma was considered. IHC expression of the Mic2 gene product (CD-99) in PNET is helpful in separating PNET from other small round-cell tumors such as sarcomas. Further IHC revealed CK negativity, ruling out sarcoma and S-100 and NSE positivity with Ki-67 positivity of 70%; clinching the diagnosis of the malignant neuro-endocrine tumor. PNET is an aggressive tumor with a very poor prognosis. The treatment of choice for these tumors depends on the primary site, functional status, and the stage of the disease. Therapy involves combinations of radical surgical resection, neo-adjuvant and adjuvant chemotherapy, and irradiation.
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[Figure 1], [Figure 2]