-Case Reports-

Squamous Cell Carcinoma of Unknown Primary that Metastasized to an Inguinal Lymph Node: A Case Report

Atsuko Sugimoto¹, Kanae Nakamura¹, Kousuke Kuwahara¹, Noriko Matsumoto¹, Kotoho Oki^1,2 and Rei Ogawa¹

¹Department of Plastic, Reconstructive, and Aesthetic Surgery, Nippon Medical School Hospital, Tokyo, Japan
²Hakujikai Memorial General Hospital, Tokyo, Japan

Carcinoma of unknown primary (CUP) is a malignant tumor with histological characteristics indicating metastasis in a patient with an unidentified primary lesion after whole-body evaluation at the time of examination. CUP incidence is similar in men and women, and average age at diagnosis is 60 years. Reports of overall incidence vary but CUP is believed to account for 1-5% of all cancers. We encountered a case of apparently metastatic squamous cell carcinoma of the inguinal region in a patient without a detectable primary lesion. We report this case and review the literature on CUP, to increase awareness of this rare lesion.

J Nippon Med Sch 2022; 89: 454-459

Keywords
carcinoma of unknown primary, squamous cell carcinoma, lymph node metastasis

Correspondence to
Atsuko Sugimoto, Department of Plastic, Reconstructive, and Aesthetic Surgery, Nippon Medical School Hospital, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan
atsukos@nms.ac.jp

Received, December 9, 2020
Accepted, March 17, 2021