Crystal storing histiocytosis clinically mimicking metastatic carcinoma: Report of a case and reviews of literature.

BACKGROUND Crystal storing histiocytosis (CSH) is a rare disorder characterized by accumulation of histiocytes containing crystalline material inclusions. This entity can be misdiagnosed as infection or tumor. We present a case of idiopathic CSH mimicking metastatic squamous cell carcinoma in a cervical lymph node and review of literature regarding this rare entity. METHODS AND RESULTS The patient was a 70-year-old man with a medical history of squamous cell carcinoma of the right base of the tongue. The patient presented with an enlarged cervical lymph node, which was clinically diagnosed as metastatic carcinoma. At intraoperative consultation, it was unexpectedly discovered that the lymph node exhibited extensive histiocytosis containing crystal materials. Final pathology identified "crystal storing histiocytosis" because of amyloidal depositions. No metastatic carcinoma was seen. CONCLUSION After 10 months of follow-up, the patient is disease free. To the best of our knowledge, this unusual clinical presentation is the first to describe CSH mimicking a metastatic carcinoma.