To investigate correlation between growth pattern of cultivated retinoblastoma (RB) cells from three Iranian RB patients and their histopathologic features.

RB cells from three Iranian patients (MM, NR, and MS) were cultivated in DMEM supplemented with 15% FBS for four weeks in each passage. Fresh medium was added on a weekly basis and immunocytochemistry for synaptophysin was performed. Growth pattern of cultivated RB cells was studied during three consecutive passages and compared between three cases in the light of histopathologic data.

Cultivated RB cells from MM and NR demonstrated an adherent growth pattern in the 2nd week that was enhanced by the 4th week. The RB tumorspheres adhered to the bottom of the flask while surrounded by fibroblasts. Histopathologic diagnosis in MM and NR was a well-differentiated RB without optic nerve involvement. Such an adherent growth was not observed in cultivated RB cells from MS, in which the histopathologic analysis revealed a poorly-differentiated RB with optic nerve intrusion and prominent choroidal invasion.

Result of our case series suggest that adherent growth of cultivated RB cells might have a correlation with the differentiation degree of tumor cells and the lack of optic nerve involvement in histopathology.