Prognostic suggestion in the evaluation of solid component in poorly differentiated adenocarcinoma of the lung.
Pulmonary adenocarcinoma composed of pure or predominant solid components is reported to be a highly malignant tumor. However, the existence of solid components and its connection with biological behavior have not been well documented. To answer this question, we histologically subclassified poorly differentiated adenocarcinoma (P/D Ad Ca) into solid type and non-solid type, and compared the biological behavioral characteristics.


METHODS
All histological specimens of surgically resected primary lung carcinoma diagnosed as P/D Ca or large cell carcinoma in Nippon Medical School Hospital were re-evaluated according to the 1999 WHO manual. The cases re-evaluated as P/D Ad Ca were further divided into solid type and non-solid type according to our original definition: the solid type contains solid components where a glandular structure is not recognized in more than one high-power field, while in the non-solid type, a small glandular structure is observed in every high-power field. The differences in the occurrence of lymph node metastasis were assessed by Fisher's exact test.


RESULTS
Among 109 cases satisfying both histological and clinical investigation, 45 cases were re-evaluated as P/D Ad Ca; solid type (n=22), and non-solid type (n=23). Lymph node metastases occurred at a higher rate in the solid type than in the non-solid type (p<0.01).


CONCLUSIONS
Patients with solid type Ad Ca have reached a more advanced stage than patients having non-solid type due to high metastatic rate to lymph nodes. These results suggest that we should not overlook solid components even if the solid components are the focal lesion. This sub-typing alerts clinicians to survey metastases, and may contribute to therapeutic strategies in the future.
Satoh
Etsuko
E
Nippon Medical School, Tokyo, Japan.
Kawamoto
Masashi
M
Nakayama
Tomoko
T
Kunugi
Shinobu
S
Yoshimura
Akinobu
A
Haraguchi
Shuji
S
Okada
Daisuke
D
Tanaka
Shigeo
S
Sugisaki
Yuichi
Y
Fukuda
Yuh
Y
Koizumi
Kiyoshi
K
D000230:Adenocarcinoma / Q000473:pathology*; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011379:Prognosis