Purpose: To describe severe fibrovascular proliferation that developed in the optic disk region in an atypical form of retinopathy of prematurity (ROP). Methods: Retrospective observational case reports. Results: Four patients (8 eyes) with ROP were included. Three patients were born very prematurely (24-25 weeks of gestational age; weight, 500-1,000 grams); 1 patient was born at 33 weeks of gestational age. Among all eight eyes of four patients who received prompt ROP screening and underwent laser photocoagulation, six eyes had atypical and severe fibrovascular proliferation mainly in the optic disk region; the other two eyes, including one eye with classic ROP and one eye with aggressive posterior ROP, did not have the atypical form. All eight eyes had a total to partial retinal detachment. Among the six eyes with the atypical form, early vitreous surgery with lensectomy was possible in three eyes; only late vitreous surgery with lensectomy was possible in two eyes; one eye was inoperable. Three eyes had a partial or complete reattachment, whereas three eyes had a total retinal detachment. Among the six eyes with atypical fibrovascular proliferation, only two eyes obtained light perception vision. Conclusion: An atypical and severe form of ROP, in which fibrovascular proliferation grew mainly from the optic disk region, needs further investigation for treatment in addition to laser photocoagulation and vitreous surgery.