Mikulicz’s disease with severe thrombocytopenia following autologous stem cell transplantation in a multiple myeloma patient

We report the first case of Mikulicz’s disease (MD) occurring 2 years after autologous peripheral blood stem cell transplantation (PBSCT) for multiple myeloma (MM). A 70-year-old man developed bilateral enlargement of parotid and submandibular glands. The patient had previously received 2 courses of autologous PBSCT for IgG-κ type MM, and had been stable for 2 years. This salivary gland enlargement was initially felt to represent a recurrence of MM, since along with gland swelling, IgG was also elevated. However, repeated biopsy of the left submandibular gland revealed chronic sclerosing sialadenitis rather than plasmacytoma. Results of salivary gland scintigraphy, serological testing, and absence of sicca symptoms also supported the diagnosis of MD. Concurrently, the patient developed severe thrombocytopenia (0.8 × 10⁴/μl). Bone marrow biopsy showed abundant megakaryocytes, suggesting enhanced platelet destruction. After high-dose steroid and immunoglobulin therapy, the platelet count gradually returned to normal with complete resolution of the salivary gland enlargement. No apparent signs of MM recurrence were documented during these clinical events.