Mixed squamous cell and glandular papilloma of the lung―A case report and literature review in Japan

Clinicopathological feature of a resected large mixed squamous cell and glandular papilloma: A case report

“…Although no malignancy was observed on postoperative histopathological examination, the choice of surgical procedure was considered appropriate. Although there have been no cases of recurrence after complete resection of MSGP in previous reports [2] , [3] , we plan to carefully follow-up with the patient.…”

“…HPV infection has been reported to be associated with the etiology of SP, but not with that of GP or MSGP [1] , [3] . Therefore, MSGP is considered to be caused by squamous metaplasia of a part of GP [8] .…”

“…Immunohistochemical staining suggested that squamous metaplasia was not caused by HPV infection; rather, it was caused by a pseudo-koilocytosis change associated with squamous metaplasia. Most cases of MSGP, including the present case, reportedly tested negative for HPV infection on immunohistochemical staining or in situ hybridization [1] , [3] , [8] . However, one case of MSGP with HPV (HPV 16, 35, and 51) infection diagnosed by polymerase chain reaction (PCR) was recently reported [9] .…”

“…In this case, although a GP was suggested by TBLB, malignancy could not be ruled out before the surgery owing to FDG-PET/CT imaging findings, elevated tumor marker levels, and histopathological findings of biopsy materials. Generally, malignancy is only revealed by postoperative histopathological examination of resected tumors in patients with SEP [2] , [3] . In the present case, the tumor was large, and left upper lobectomy was performed, instead of lingual segmentectomy, for complete resection with a sufficient surgical margin.…”

“…Thus, MSGP is the rarest subtype of SEP, and its etiology and clinicopathological characteristics remain unclear. In most cases, MSGP is reported to be ≤3 cm in size; a large MSGP is very rare [3] . To the best of our knowledge, the largest MSGP reportedly measured 11 cm in size to date, and this case is unique as it occurred in the periphery of the lung and was associated with interstitial pneumonia [4] .…”