title: A case of pulmonary hamartoma showing rapid growth.
abstract: A 65-year-old man was admitted for detailed examination of a growing nodular shadow in the left lung. The nodular shadow was initially detected in a routine chest X-ray check-up in March 2012 that warranted regular chest X-ray follow-up. The nodular shadow increased in size from 12 × 15 mm to 15 × 20 mm within five months. The calculated tumor doubling time (TDT) in our case was approximately 132.2 days. A malignant tumor was strongly suspected based on the rapid growth, and tumorectomy was thus performed. Cartilaginous tissue accounted for most of the pathological specimen, but a small amount of an epithelial component was observed histologically, and we diagnosed a hamartoma. Hamartoma generally shows slow annual growth, but it is important to recognize that rapid enlargement occurs in some cases.
authors.affiliation: Department of Infection, Allergy, Clinical Immunology and Laboratory Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan.
authors.forename: Masamichi
authors.initials: M
authors.lastname: Itoga
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Masahide
authors.initials: M
authors.lastname: Takeda
authors.forename: Yuki
authors.initials: Y
authors.lastname: Moritoki
authors.forename: Mami
authors.initials: M
authors.lastname: Tamaki
authors.forename: Kenji
authors.initials: K
authors.lastname: Nakazawa
authors.forename: Toru
authors.initials: T
authors.lastname: Sasaki
authors.forename: Hayato
authors.initials: H
authors.lastname: Konno
authors.forename: Ikuo
authors.initials: I
authors.lastname: Matsuzaki
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Ueki