Cytologic and histologic features of pigmented pleomorphic xanthoastrocytoma: A case report and literature review.

In the central nervous system, the presence of pigment in astrocytic tumors is rare. Only nine cases were reported in the English literature: one ganglioglioma, one pilocytic astrocytoma, and seven cases of pleomorphic xanthoastrocytoma (PXA). Though squash cytology is a common and useful tool for intraoperative diagnosis during brain tumor surgeries, the cytologic findings of pigmented PXA have not been recorded previously. We present a 32-year-old woman with a mass in her medial right temporal lobe. Intraoperative squash cytology examination demonstrated pleomorphic tumor cells containing cytoplasmic pigment granules. The subsequent tissue section and additional workup revealed a PXA with melanosomal melanin pigment deposits. While conventional PXA has to be differentiated from high-grade tumors such as glioblastoma, in the pigmented variant the presence of pigment can cause further diagnostic confusion with other pigmented tumors, in particular melanoma. It should be added into the differential diagnoses when a brain tumor smear shows nuclear pleomorphism and intracytoplasmic pigment particles.