Phosphoglyceride crystal deposition disease requiring differential diagnosis from malignant tumors and confirmed by Raman spectroscopy: A case report.

BACKGROUND: Phosphoglyceride crystal deposition disease (PCDD) is a rare acquired disease in which phospholipid crystals deposit in bone and soft tissue long after surgery, trauma, or repeated injections. CASE SUMMARY: A 60-year-old-woman was referred to our department because of multiple abdominal masses after open splenectomy for idiopathic thrombocytopenic purpura 29 years earlier. All the masses showed marked fluorodeoxyglucose (FDG) uptake on 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) and were strongly suspected to be malignant tumors. Surgical biopsies were performed, and the abdominal masses were found to be aligned vertically, three in a row, along the tissue layers cut in the patient's previous surgery. Pathological finding of the specimens showed foreign body granuloma consisting of histiocytes and multinucleated giant cells accumulating around needle-like crystals. The crystals were confirmed as phosphoglyceride by Raman spectroscopy, and PCDD was diagnosed. To our knowledge, this is the first report of PCDD diagnosed by Raman spectroscopy. CONCLUSION: We made a definitive diagnosis of PCDD in a patient with multiple tumors showing marked FDG uptake on 18F-FDG-PET by incisional biopsy and compo- sition analysis using Raman spectroscopy, a method that has not previously been reported for the diagnosis of PCDD.