Myeloid sarcoma involving lacrimal sac masquerading as chronic dacryocystitis: a case presentation and review of the literature

To report a case of myeloid sarcoma involving the lacrimal sac masquerading as persistent or recurrent dacryocystitis and to highlight diagnostic pitfalls relevant to lacrimal surgeons. A 31-year-old woman presented with a swelling in the lacrimal sac area and epiphora for one year following two prior dacryocystorhinostomies performed elsewhere for presumed chronic dacryocystitis. Imaging revealed a soft-tissue mass involving the lacrimal sac with nasolacrimal duct widening and an adjacent focal bony defect. Incisional biopsy demonstrated a dense infiltrate of myeloperoxidase (MPO)-positive blasts, confirming myeloid sarcoma. Subsequent haematological evaluation confirmed acute myeloid leukaemia (AML). The patient was treated with AML-directed systemic chemotherapy, resulting in complete resolution of the lacrimal sac mass and sustained remission at the 18-month follow-up. Based on our review of the published literature, this appears to represent only the fourth clinicopathologically documented case of myeloid sarcoma involving the lacrimal sac reported in English-language literature. Myeloid sarcoma of the lacrimal sac is exceedingly rare and may clinically mimic chronic dacryocystitis. A persistent firm-to-hard mass in the lacrimal sac area should prompt an early biopsy with appropriate immunophenotyping. As myeloid sarcoma may represent the initial manifestation of acute myeloid leukaemia, prompt haematological evaluation is warranted following histopathological diagnosis.