monotonous, stippled, round, smoothcontoured nuclei and scanty acidophilic or vacuolated cytoplasm. The cells are surrounded by a loose fibrillary stroma that is traversed by delicate capillaries. Ill formed perivascular rosettes are appreciated. Mitotic activity is inconspicuous. Many cells contain granular blackish brown pigment. There is no vascular endothelial proliferation or necrosis. central neurocytoma have been described in the literature to date. The first account of a pigmented central neurocytoma identified cytoplasmic lipofuscin granules.13 In a similar subsequent case an intimate association of lipofuscin and Fig. 1 Im m u n o h is to c h e m is tr y s h o we d cytoplasmic staining for synaptophysin but not for glial fibrillary associated protein(gfap), epithelial membrane antigen (EMA), neuron specific enolase (NSE), chromogranin, or neurofilament.ki 67 proliferation index was less than 2%. Prussian blue staining was negative. Periodic acid-schiff (PAS) staining was positive. Diagnosis Central neurocytoma (pigmented), septum pellucidum. (a) Discussion As such pigment is an infrequent feature of neuroepithelial neoplasms. The normally melanotic neoplasms like meningeal melanocytoma and intracranial malignant melanoma are indeed rare. Exceptional cases of pigmented lesions have been described for tumour types that normally do not contain the pigment for example, choroid plexus papilloma, ependymoma and carcinoma were found to have both lipofuscin and neuromelanin.9,10,11,12 Other examples are medulloblastoma-medulloepithelioma, schwannoma and meningioma. The accumulation of pigment in neuroepithelial tumours has not been associated with a change in biological behaviour.9,10 Only rare cases of pigmented Bombay Hospital Journal, Vol. 53, No. 2, 2011 (b) H and E stained sections showing (a) monotonous population of small cells having round nuclei and pale acidophilic cytoplasm. (b) In the right half many pigment containing cells are seen. H and E x 380 239
Fig. 2 Fig. 3 (a) Figure shows PAS positivity in tumour cells indicating the presence of neuromelanin and lipofuscin X380 (b) (a) Synaptophysin immunohistochemistry showing diffuse cytoplasmic staining. (b) This view shows marked decrease in the amount of melanin pigment which has been bleached with potassium permanganate. X 380 neuromelanin was noted.14 The authors suggested autocatalytic peroxidation of lipofuscin as a possible mechanism for neuromelanin formation. It was also thought to be a manifestation of the low turnover rate of tumour cells, compatible with the usually slowly growing nature of 240 central neurocytoma. The current case is unique because it contained all the three pigments (neuromelanin, melanin and lipofuscin) such a case has not been previously described in the literature.1,2 Marked reduction in the amount of pigment on bleaching (potassium permanganate) indicates melanin (Fig. 2b) and positive staining for periodic acidschiff indicates the presence of neuromelanin and lipofuscin. (Fig. 3) The present case is reported to highlight this rare morphological feature of central neurocytoma. References 1. Figarella-Branger D, Soylemezoglu F, Kleihues P, Hassoun J, Central neurocytoma. In : Kleihues P, Cavenee WK (eds) World Health Organization classification of tumors : pathology and genetics of tumours of the nervous system. IARC Press, Lyon, pp 2000;107-109. 2. Hassoun J, Gambarelli D, Grisoli F, Pellet W, Salamon G, Pellissier JF, Toga M, Central neurocytoma. An electronmicroscopic study of two cases. Acta Neuropathol (Berl) 1982;56:151156. 3. Stephan CL, Kepes JJ, Arnold P, Green KD, Chamberlin F Neurocytoma of the cauda equina. Case report. J Neurosurg 1999; 90:247-251. Bombay Hospital Journal, Vol. 53, No. 2, 2011