An extremely rare case of stromal micropapillary predominant lung adenocarcinoma is presented in this study. A 70-year-old woman visited our hospital because of an abnormal shadow on chest X-ray. Chest computed tomography revealed a nodule in the left lower lobe and a mass in the left upper lobe. She underwent an exploratory thoracotomy owing to the suspicion of advanced lung cancer. Pathological examination of the left lower lobe nodule revealed tumour cells with more than half the tumour cells showing stromal micropapillary pattern (SMP), consisting of tumour cells invading the fibrotic stroma. In general, micropapillary adenocarcinomas in the lung form an aerogenous micropapillary pattern (AMP), in which tumour cells float in alveolar spaces. Because the prognosis of SMP lung adenocarcinomas is known to be worse than that of AMP lung adenocarcinomas and have a high frequency of epidermal growth factor receptor mutations, the discrimination of SMP from AMP is important for both pathologists and clinicians.

Background Pulmonary resection with mediastinal lymph node dissection for treating primary lung cancer could sometimes causes chylothorax as a postoperative complication. This study examined the validity of treatments for chylothorax in our hospital. Methods We evaluated 2019 patients who underwent lobectomy, bilobectomy, or pneumonectomy with mediastinal lymph node dissection for primary lung cancer at Shizuoka Cancer Center Hospital, Shizuoka, Japan, between September 2002 and March 2018. The diagnostic criteria for postoperative chylothorax were that the drainage from the pleural drain was evidently white and turbid, or the pleural effusion contained a triglyceride level of > 110 mg/dL. The clinical courses and treatments were retrospectively reviewed. Results Postoperative chylothorax occurred in 37 patients (1.8%), 20 men and 17 women, with a median age of 70 years (33–80). A low-fat diet was instituted to all patients; 35 cases improved with conservative treatment, and 2 cases required reoperation. Nine cases had a drainage volume ≥ 500 mL one day following the low-fat diet commencement, which was resolved with conservative treatment and decreased drainage was observed on the third day of treatment in seven of those cases. Two cases with excessive drainage of ≥ 1000 mL in one day and systemic symptoms associated with chyle loss needed surgery. Conclusions Even when the daily drainage volume exceeds 500 mL following a low-fat diet, there were many cases that could be cured conservatively. The indication for surgery needs to be carefully considered.

Descending necrotizing mediastinitis (DNM) is a potentially lethal disease that originates from a deep neck infection (DNI); it is often associated with an immunocompromised state. Hyperimmunoglobulin E syndrome (HIES) is an extremely rare complex immune deficiency characterized by recurrent abscesses of staphylococcal etiology. A rare case of a 34‐year‐old woman wherein HIES putatively promoted the development of DNI into DNM is described. She presented with cervical purulent lymphadenitis and retropharyngeal abscess. Despite immediate cervical drainage and use of broad‐spectrum antibiotics, she developed DNI and subsequently DNM. Mediastinal drainage with thoracotomy and subsequent deep neck drainage were performed. Bacterial culture of the abscess isolated methicillin‐resistant Staphylococcus aureus (MRSA). Although a postoperative recurrent deep neck abscess required a second surgery, we succeeded in conservative remission of recurrent mediastinal abscess with long‐term use of anti‐MRSA drugs. Sufficient drainage under thoracotomy and robust administration of postoperative antibiotics resulted in successful management of HIES‐associated DNM.

Adenosquamous lung carcinoma (AdSqLC) has a worse prognosis than adenocarcinoma (ADC) or squamous cell carcinoma (SQCC). Micropapillary pattern in lung ADC is an additional poor prognostic factor. We describe a rare case of AdSqLC with epidermal growth factor receptor (EGFR) mutation in both the micropapillary‐ADC and SQCC components, showing long‐term response to gefitinib. A 60‐year‐old woman underwent right lower lobectomy for primary lung cancer. Histopathological examination demonstrated adenosquamous carcinoma comprising micropapillary‐ADC and moderately differentiated SQCC. EGFR exon 19 deletions mutation was detected in both the ADC and SQCC components. Gefitinib was administered for multiple metastatic recurrences on bilateral lung, resulting in remarkable shrinkage of visible lesions. The efficacy of gefitinib lasted for 31 months after the induction. AdSqLCs harbouring the EGFR mutation in both the ADC and SQCC components may well benefit from EGFR tyrosine kinase inhibitors, especially when they contain micropapillary‐ADC component that correlates with frequent EGFR mutations.

PURPOSE Several studies reported the possibility of predicting genetic abnormalities in non–small-cell lung cancer by deep learning (DL). However, there are no data of predicting ALK gene rearrangement ( ALKr) using DL. We evaluated the ALKr predictability using the DL platform. MATERIALS AND METHODS We selected 66 ALKr-positive cases and 142 ALKr-negative cases, which were diagnosed by ALKr immunohistochemical staining in our institution from January 2009 to March 2019. We generated virtual slide of 300 slides (150 ALKr-positive slides and 150 ALKr-negative slides) using NanoZoomer. HALO-AI was used to analyze the whole-slide imaging data, and the DenseNet network was used to build the learning model. Of the 300 slides, we randomly assigned 172 slides to the training cohort and 128 slides to the test cohort to ensure no duplication of cases. In four resolutions (16.0/4.0/1.0/0.25 μm/pix), ALKr prediction models were built in the training cohort and ALKr prediction performance was evaluated in the test cohort. We evaluated the diagnostic probability of ALKr by receiver operating characteristic analysis in each ALKr probability threshold (50%, 60%, 70%, 80%, 90%, and 95%). We expected the area under the curve to be 0.64-0.85 in the model of a previous study. Furthermore, in the test cohort data, an expert pathologist also evaluated the presence of ALKr by hematoxylin and eosin staining on whole-slide imaging. RESULTS The maximum area under the curve was 0.73 (50% threshold: 95% CI, 0.65 to 0.82) in the resolution of 1.0 μm/pix. In this resolution, with an ALKr probability of 50% threshold, the sensitivity and specificity were 73% and 73%, respectively. The expert pathologist's sensitivity and specificity in the same test cohort were 13% and 94%. CONCLUSION The ALKr prediction by DL was feasible. Further study should be addressed to improve accuracy of ALKr prediction.