Cytopathological diagnosis of adult retinoblastoma in a vitrectomy specimen

Abstract

Retinoblastoma (RB) is extremely rare in adults. We describe a case of RB diagnosed by cytology in a vitrectomy specimen of a 23-year-old patient who presented with diminished visual acuity and retinal detachment in the absence of a clinically-visible mass. Cytological examination of the vitreous fluid showed clusters of loosely cohesive atypical cells with high nuclear to cytoplasmic ratio and "salt and pepper" chromatin pattern in a background of normal neuronal retinal cells. Nuclear molding was present as well as numerous apoptotic bodies. The cells were focally positive for epithelial markers and showed strong and diffuse positivity for neuroendocrine markers. Ki-67 stained 90% of the "atypical cells" nuclei, in contrast to nonneoplastic retinal neuronal cells, which were negative for the marker. A diagnosis of RB was rendered, and subsequently was confirmed in the enucleation specimen. The cytological differential diagnosis is discussed as well as the role that cytology and immunohistochemistry can play in differentiating neoplastic cells from normal retinal cellular elements in vitreous fluid specimens.

Adult onset retinoblastoma

“…[ 4 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 ] From 2005 onward, there has been a sudden proliferation of cases where 23 more cases have been published including 16 cases reported in the last 3 years. [ 5 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 ]…”

“…However, in three cases, it was not identified initially on clinical examination but later confirmed on imaging. [ 5 26 ] The majority of the eyes (28 out of 45) had a single mass; one had two separate retinal lesions[ 23 ] whereas multiple lesions were noted in two eyes. [ 29 38 ] Data are not available on 13 cases.…”

“… Adult onset Coats disease[ 31 ] Retinal astrocytoma Metastatic carcinoma[ 5 29 ] Amelanotic melanoma[ 5 35 37 ] Intraocular lymphoma Vasoproliferative tumor[ 5 ] Endophthalmitis or panophthalmitis Fungal granuloma[ 32 ] Ocular cystecercosis[ 23 ] Retinal inflammatory diseases[ 26 ] Intraocular medulloepithelioma Retinocytoma Neovascular glaucoma (in the presence of anterior segment signs with poor view of fundus). [ 38 ] …”

“…The examination could provide limited information such as the presence of small round malignant cells in ten cases whereas in three cases smear was acellular. Cytology could differentiate nonmalignant masquerades such as Coats disease[ 31 ] or posterior uveitis[ 26 ] but was inconclusive in distinguishing primary and metastatic tumor and lead to delayed diagnosis in one case[ 28 ] and misdiagnosis in another. [ 5 ] In general, preoperative FNAB is not routinely performed in RB for risk of tumor seeding.…”

“…[ 33 ] Two cases underwent pars plana vitrectomy for retinal detachment with unsuspected RB ending up finally in enucleation. [ 26 29 ] Seven eyes had to be enucleated after the failure of other treatment modalities. No surgery was needed in one case of orbital RB but exenteration was done in other two.…”