Cytodiagnosis of alveolar soft part sarcoma: Report of two cases with special emphasis on the first orbital lesion diagnosed by aspiration cytology
A 25-year-old male presented with mild pain in the right eye on and off since 1 year, along with progressive proptosis and periorbital swelling for last 4 months. He complained of diminution of vision and diplopia since 3 months, which initially progressed but became static at the time of presentation. There was no history of any trauma, loss of consciousness or fever. Examination of extraocular muscles showed restricted upward gaze. Computed tomography (CT) scan showed a mildly enhancing right orbital mass abutting superior rectus muscle with displacement of eyeball anteriorly, inferiorly and laterally. Magnetic resonance imaging (MRI) revealed a lobulated right supraorbital extradural mass lesion, predominantly occupying superomedial extraconal compartment and infiltrating intraconally. The mass was isointense to grey matter and showed heterogeneous contrast enhancement. No intracranial extension was noted. Aspiration cytology smears revealed scattered and groups of monotonous population of cells with round to oval nuclei, prominent large nucleoli, few with intranuclear inclusions and abundant pale finely vacuolated to granular cytoplasm. Few cells also showed disrupted cytoplasm, with fraying of the cytoplasmic margins []. Few larger fragments had cohesive cells in clusters, while other areas showed central round nuclei in a sea of cytoplasm. Bare nuclear forms were also noted. Periodic acid Schiff (PAS) with diastase stain revealed magenta pink intracytoplasmic granules and occasional slender crystalline structures []. The tumor, located between orbital roof and globe, was excised through right supraorbital keyhole craniotomy. The excised mass was soft to firm, highly vascular, non-suckable, with ill-defined plane of cleavage. Histopathology showed characteristic alveolar pattern and cellular morphology of ASPS []; however, the immunohistochemical panel applied was not contributory. Electron microscopy showed increased number and abnormal clustering of mitochondria, prominent endoplasmic reticulum, glycogen vacuoles, along with few electron-dense bodies []. However, the characteristic rhomboid crystalline lattice was not seen. On extensive workup and thorough imaging, no mass lesion was detected at any other site. Radiation was difficult in this patient with orbital lesion due to the fear of visual compromise; hence, he was offered chemotherapy, with no further growth of the lesion or metastatic disease on 6 months of follow-up.