A Rare Case of Congenital Ewing Sarcoma/PNET of the Scapula Sree Rekha Jinkala, MD,* Debdatta Basu, MD,* Dinesan Mathath, MD,w Biswajit Dubashi, MD, DM,w and Arpita Bhaumik, MBBSz Summary: Ewing sarcoma (ES)/primitive neuroectodermal tumors (PNET) are known to occur at both central and peripheral loca- tions, as well as at skeletal and extraskeletal sites. They most commonly occur in the first 2 decades of life. We report a rare case of congenital Ewing sarcoma/primitive neuroectodermal tumor arising from the scapula. Key Words: Ewing sarcoma, PNET, congenital (J Pediatr Hematol Oncol 2014;36:e134–e135) E wing sarcoma and primitive neuroectodermal tumor are small blue round cell tumors. These tumors show varying degrees of neuroectodermal differentiation. Although once viewed as distinct entities, ES, Askin tumor, and PNET are now considered together as members of the Ewing family of tumors. 1 The term “peripheral PNET” was later applied to separate them from unrelated lesions of the central nervous system. 2 Congenital PNETs are more common intracranially, and there are only rare reports of congenital ES/PNET arising in peripheral location. 3–7 We report one such rare case of a congenital ES/PNET. CASE REPORT A 1-month-old male infant weighing 2.5 kg was brought to the medical oncology outpatient department with complaints of swelling in left shoulder since birth. The baby was born at term by vaginal delivery with a birth weight of 2.5 kg and a normal ante- natal history. The swelling was 1.5 cm at birth but rapidly increased over 1 month, measuring about 10  8 cm, and occupying left supraclavicular and interscapular region with congested vessels seen over the swelling. Debulking was done at a peripheral center, and the patient was referred to our institute for further management. Regional ultrasonography showed a 10  7 cm heterogenous solid lesion in the intermuscular plane with multiple echogenic foci within, extending into supraclavicular area. There was no evidence of any intrathoracic extension. A computed tomography scan of the thorax and the abdomen showed a 10 10  10 cm enhancing soft tissue mass in the muscle plane of left scapular region with erosion of the medial and lateral borders of the scapula and infil- tration into the paravertebral muscles (Fig. 1). The histomorphology of the tumor showed monomorphic small blue round cells arranged in nests separated by fibrous septa. The tumor cells had scant cytoplasm, round to oval nuclei with speckled chromatin, and frequent mitosis (Fig. 2). Rosettes were not seen. Immunohistochemical analysis revealed that the tumor cells were CD99 positive (Fig. 2 inset) and negative for leukocyte common antigen, desmin, chromogranin, synaptophysin, TdT, CD10, and CD20. Histopathologic diagnosis of Ewing sarcoma/ PNET was given. A bone scan taken showed primary pathology in left shoulder with lesions involving right shoulder (scapula region) and right femur proximal and distal end suggestive of metastases. A staging bone marrow examination revealed infiltration of the bone marrow by atypical cells, which were positive for CD99. Cytogenetic study to demonstrate t(11;22) could not be carried out as it was not available at our institute. As the baby showed metastatic disease with bone marrow involvement (stage IV), only conservative treatment was given and prognosis was explained to the parents. DISCUSSION Tumors that present within one month of life are considered as congenital tumors. 8 The most common fetal/ congenital neoplasms are neuroblastomas, teratomas, leu- kemias, soft tissue tumors, and brain tumors. Collectively, these tumors constitute approximately 85% of all con- genital tumors with renal tumors, liver tumors, and reti- noblastomas constituting the majority of the remainder. 8 PNETs are rare congenital tumors and are commonly intracranial, presenting with macrocephaly or hydro- cephalus. Congenital ES/PNET is a rare disease, and there are only a few reports in the literature arising at different sites. Atla et al 3 reported a case of congenital extraskeletal ES/ PNET of the chest wall detected in the antenatal ultrasound at 31 to 32 weeks of gestation. Saito et al 4 reported a case of FIGURE 1. A computed tomography scan—showing soft tissue mass in the muscle plane of left scapular region with erosion of the medial and lateral borders of the scapula and infiltration into the paravertebral muscles. Received for publication December 31, 2012; accepted August 20, 2013. From the Departments of *Pathology; wMedical oncology; and zRadiodiagnosis, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India. The authors declare no conflict of interest. Reprints: Debdatta Basu, MD, Department of Pathology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry 605006, India (e-mail: ddbasu@gmail.com). Copyright r 2013 by Lippincott Williams & Wilkins CLINICAL AND LABORATORY OBSERVATIONS e134 | www.jpho-online.com J Pediatr Hematol Oncol  Volume 36, Number 2, March 2014