The eye and the ocular adnexae are rare sites for malignant non-Hodgkin lymphoma (NHL). Based on their anatomical location, intraocular lymphomas must be discerned from NHL of adnexal structures including conjunctiva, lacrimal gland, and orbit. Whereas the latter group mostly consists of indolent extranodal marginal zone B‑cell lymphomas of mucosa-associated lymphoid tissue (MALT) type or secondary manifestations of systemic NHL, most primary intraocular lymphomas are classified as diffuse large B‑cell lymphomas (DLBCL) and are considered a variant of primary DLBCL of the central nervous system. The most common form is primary vitreoretinal lymphoma (PVRL), which presents with nonspecific symptoms and is difficult to discern from uveitis. Diagnosis of PVRL is usually made by cytological, immunocytochemical, and molecular analysis of vitreous aspirates. Degenerative changes, limited material, and the occurrence of pseudoclonality in the molecular analysis of B‑cell clonality can hamper diagnostic assessment. Novel techniques such as detection of MYD88 mutations common in PVRL can increase diagnostic sensitivity. Close cooperation with clinical colleagues and rapid specimen processing are fundamental for successful diagnosis.