Microscopic findings, immunohistochemical staining, and whole-body fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) of primary adrenal T-cell lymphoma. (A) Aqueous humor aspiration showed infiltration of atypical lymphoid cells. (B) Bone marrow (BM) aspiration showed infiltration of atypical lymphoid cells with irregular nuclear membrane, coarse chromatin, basophilic cytoplasm and fine azurophilic granules. (C) BM biopsy showed infiltration of lymphoma cells with “fried egg” pattern. (D) FDG avid lesions in the adrenal glands. (E) Diffuse FDG uptake in the BM. (F) Absence of FDG avid intra-orbital and intra-ocular mass lesions. (G) Adrenal aspiration showed lymphoma infiltration. (H) CD34 immunohistochemistry (IHC) of the BM biopsy highlighting intra-sinusoidal pattern. (I) CD8 positivity in the BM lymphoid infiltrate. (J, K) Diffuse and intense FDG uptake in both the adrenal glands (A, B, & G: May-Grünwald Giemsa stain; C: Hematoxylin and eosin stain).