Sacrococcygeal myxopapillary ependymoma with anaplastic ependymoma component in an infant
An 11-month-old female child, with appropriate for age social and motor milestones, presented with a subcutaneous sacrococcygeal mass of 1 month duration. The skin over the lesion was stretched but not fixed to it. The mass was firm in consistency with restricted mobility. There was no bladder bowel disturbance. Ultrasound examination showed a large, solid mass with cystic component having mixed echogenicity, measuring 6.5 × 6 × 5.5 cm in the sacrococcygeal region. Magnetic resonance imaging (MRI) of the pelvis was limited only to the axial and coronal planes in T2-weighted sequence, which exhibited a 6 × 5.8 × 5 cm solid mass located in the midline posterior pelvis. The mass straddled across the sacrococcyx and was dumbbell shaped, with almost equal pre- and post-sacral components [Figure –]. The mass within the pelvis was insinuating around the rectum, and a small part was seen extending posterior and lateral to the urinary bladder. No pelvic lymphadenopathy was noted. Provisional clinical and radiological diagnosis was sacrococcygeal teratoma of Altman type II based on anatomical location and extension.\nThe excision of sacrococcygeal mass was performed under general anesthesia after placing the patient in a prone (jackknife) position. The rectum was packed with gauze soaked in povidone iodine to prevent contamination of surgical field. Using the posterior sacral approach, a chevron skin incision was made. The post-sacral component of tumor was mobilized, but there was difficulty in dissection of the pre-sacral component of the tumor. The patient's position was changed to laparotomy lithotomy position. On abdominal exposure, the tumor's distal margin was mobilized from the posterior rectal wall, and lateral margins from the urinary bladder, and delivered by sacral incision. During surgery, care was taken to prevent injuries to the urinary bladder, sphincter, posterior rectal wall, pre-sacral venous plexus and sacral nerve roots. Hence, the tumor was excised en block with the combined approach and coccygectomy was performed. Post-operative period was uneventful.\nMorphological examination showed an irregular mass with peripherally attached fat and skeletal muscle. Cut-surface was solid-cystic with focal papillae, myxoid areas and enclosed coccyx []. Microscopy revealed a tumor composed of solid and cystic areas delineated by fibrocollagenous septae. The predominant component of tumor had characteristic perivascular rosettes and papillae with vascular cores lined by cuboidal to low columnar ependymal cells having eccentric nucleus and cytoplasmic processes abutting the vessel walls, and without discernible mitotic figures. The vascular cores showed myxoid change with focal hyalinization []. This predominant myxopapillary component was continuous with highly cellular areas [] composed of perivascular rosettes and canals, lined by cells having oval to elongated nuclei with coarse chromatin [Figure and ]. Nuclear overlapping and atypia, 5-6 mitotic figures/high power field (HPF) and punctate foci of necrosis were seen in this anaplastic ependymal component of the tumor. Ki-67 labeling index in the myxopapillary component was 4-5% [] and in the anaplastic component was 70% [Figure and ]. The tumor was seen infiltrating the fibrocollagenous stroma and skeletal muscles.\nThe child presented 6 weeks later with a small recurrent pre-sacral deposit and palpable right-sided inguinal lymph nodes measuring 0.5-1 cm in diameter. Serum estimation of α-feto protein (AFP) and β-human chorionic gonadotropin (β-HCG) was within normal limits. Microscopy of the excised lymph nodes revealed metastasis of the anaplastic ependymoma component of the sacrococcygeal tumor []. The patient received six cycles of Cisplatin and Etoposide. Currently, 1 year after completion of chemotherapy, there is no evidence of recurrence or further metastasis.