Quintus Chess, MD

Quintus Chess, MD, is an Interventional Cytopathologist and the Director of Outpatient Cytopathology at the Mount Sinai Union Square clinic. His work focuses on fine‑needle aspiration (FNA) biopsy, rapid on‑site evaluation (ROSE), and the integration of procedural cytopathology into outpatient clinical care.

Dr. Chess earned his medical degree from Johns Hopkins University School of Medicine and completed residency training in pathology at New York Hospital–Cornell Medical Center and Lenox Hill Hospital. He subsequently completed a fellowship in Cytopathology at Memorial Sloan‑Kettering Cancer Center, where he developed advanced expertise in diagnostic cytology and FNA technique. He later served as Chief of Cytology at North Shore Hospital.

In 1988, Dr. Chess founded Cytopath Biopsy Lab (CBL‑Path), a national reference laboratory dedicated to FNA biopsy. Under his leadership, CBL‑Path grew to more than 400 employees and became a major diagnostic resource for clinicians across the United States. The laboratory was acquired by Sonic Healthcare in 2010.

Dr. Chess’s academic and scholarly work centers on FNA biopsy, immunocytochemistry, and innovations in rapid on‑site evaluation. His benchmark study on immunoperoxidase methods in FNA received the top award at the American Society of Cytology. He is certified by examination as an expert of the International Board of Cytopathology and has been recognized by the College of American Pathologists for advanced training in FNA sonography. He also holds a U.S. patent for a spill‑free Coplin staining jar designed to improve cytology specimen handling.

At Mount Sinai, Dr. Chess leads a dedicated outpatient FNA service that integrates ultrasound‑guided biopsy, real‑time adequacy assessment, and immediate diagnostic interpretation. His clinical practice emphasizes the value of direct patient interaction in cytologic diagnosis, and he is known for his expertise in evaluating small‑sample specimens. He is one of the few non‑surgeons elected to the Society of Head and Neck Surgeons, reflecting his longstanding collaboration with multidisciplinary clinical teams.

Dr. Chess is actively involved in resident and fellow education, with a focus on interventional cytopathology, diagnostic reasoning, and the technical and interpretive aspects of FNA biopsy. His clinic serves as a high‑volume training site where trainees gain hands‑on experience in ultrasound‑guided procedures and rapid on‑site evaluation.

His ongoing work includes advancing digital and remote ROSE technologies, expanding access to high‑quality FNA services, and fostering collaborations in basic and translational research related to neoplasia and cellular pathology.