Long-term survival after incomplete resection of immunohistochemically diagnosed T0N1 lung cancer: report of a case

Lobectomy for subsegmental lymph node metastasis of unknown origin

We report a very rare case of resected subsegmental lymph node metastasis of unknown origin. Hilar (N1) lymph node metastasis of unknown origin has previously been reported, but intrapulmonary lymph node metastasis has not been reported to date. At this patient's first visit to our hospital, an abnormal nodule was found on the upper lung lobe on a chest radiograph. After 4 years' follow-up, the nodule vanished, but a tiny nodule had emerged. 2-Fluoro-2-deoxy-D-glucose positron-emission tomography (FDG-PET) computed tomography was performed, and abnormal accumulation was observed only in the newly emerged intrapulmonary nodule. Right upper lobectomy was performed and a metastatic subsegmental lymph node, but no primary lesion, was found. Our observations suggest that evanescence of a suspicious primary lesion indicates the possibility of metastasis. FDG-PET was useful in this case for detecting lymph node metastases and demonstrating that the primary and further metastatic lesions were absent.

Lymph node cancer of the mediastinum with a putative necrotic primary lesion in the lung: a case report

Background

Although mediastinal lymph node cancer is presumed to originate in the lung, the primary site is usually unidentified, so the pathological course remains unclear. We recently encountered a case of mediastinal lymph node cancer having a putative primary lesion remaining in the lung as a necrotic focus.

Case presentation

The patient was a 56-year-old man who visited our department because computed tomography screening had revealed a nodular shadow in the lingular segment. However, on positron emission tomography, fluorine-18 deoxyglucose accumulation was detected in a subcarinal lymph node and not in the nodule in the lingular segment. Biopsy of the lung tumor and the lymph node was performed via minimal thoracotomy. Intraoperative pathologic examination showed necrosis alone and no malignant findings in the lung tumor. By contrast, carcinoma was detected in the lymph node. Additional subcarinal lymph node dissection was performed. Results of postoperative histopathologic examination indicated poorly differentiated adenocarcinoma of the subcarinal lymph node. Meanwhile, the nodule in the lingular segment was speculated to be a spontaneously resolved primary focus of lung cancer.

Conclusions

In this case, the primary lung cancer focus resolved spontaneously after lymph node metastasis, explaining the pathogenesis underlying mediastinal lymph node cancer of unknown primary site. For similar cases of malignancy, aggressive treatment, including surgery, is effective.

Selection of extreme phenotypes: the role of clinical observation in translational research

Systematic collection of phenotypes and their correlation with molecular data has been proposed as a useful method to advance in the study of disease. Although some databases for animal species are being developed, progress in humans is slow, probably due to the multifactorial origin of many human diseases and to the intricacy of accurately classifying phenotypes, among other factors. An alternative approach has been to identify and to study individuals or families with very characteristic, clinically relevant phenotypes. This strategy has shown increased efficiency to identify the molecular features underlying such phenotypes. While on most occasions the subjects selected for these studies presented harmful phenotypes, a few studies have been performed in individuals with very favourable phenotypes. The consistent results achieved suggest that it seems logical to further develop this strategy as a methodology to study human disease, including cancer. The identification and the study with high-throughput techniques of individuals showing a markedly decreased risk of developing cancer or of cancer patients presenting either an unusually favourable prognosis or striking responses following a specific treatment, might be promising ways to maximize the yield of this approach and to reveal the molecular causes that explain those phenotypes and thus highlight useful therapeutic targets. This manuscript reviews the current status of selection of extreme phenotypes in cancer research and provides directions for future development of this methodology.