Masashi Kusakabe

Introduction: Adrenal oncocytomas are rare, nonfunctioning tumors composed of eosinophilic oncocytic cells whose nonspecific imaging often impedes preoperative diagnosis. We report a case of a large nonfunctioning adrenal oncocytoma with borderline malignant potential, incidentally discovered during cardiac symptom evaluation. Case Presentation: A 77‐year‐old man with an incidentally discovered retroperitoneal tumor was referred to Urology for further evaluation. Contrast‐enhanced CT revealed a 93‐mm lobulated mass with heterogeneous enhancement abutting the left kidney's upper pole. Given the tumor's size, open left nephrectomy and adrenalectomy were performed. Gross and histopathology revealed a yellowish, solid adrenal tumor composed predominantly of oncocytic cells with no invasion of the kidney. Immunohistochemistry revealed a low Ki‐67 index (approximately 2%). The tumor was classified as having borderline malignant potential (Lin–Weiss–Bisceglia criteria). Conclusion: We present a rare case of nonfunctioning adrenal oncocytoma with borderline malignant potential. Long‐term follow‐up is recommended due to the uncertain malignant potential.

Appendiceal goblet cell adenocarcinoma (GCA) is a rare amphicrine neoplasm, which recent studies have characterized as mismatch repair proficient and microsatellite stable. A 49‐year‐old male presented to our hospital with a Borrmann type 3‐like ileocecal tumor extending continuously from a markedly swollen appendix. The patient underwent ileocecal resection. Pathologically, the tumor was diagnosed as high‐grade appendiceal GCA, accompanied by lymphocytic infiltration, staged as pStage IVB. Immunohistochemistry revealed loss of MSH2 and MSH6 expression, indicating mismatch repair deficiency (dMMR), and molecular analysis confirmed microsatellite instability (MSI)‐high status. Postoperatively, the patient was treated with chemotherapy, including immune checkpoint inhibitors as second‐line therapy, which provided temporary relief of duodenal stenosis caused by tumor metastasis. However, the patient died of disease progression 37 months after surgery. To our knowledge, this is the first report of appendiceal GCA with dMMR and MSI‐high status. Our findings underscore the necessity of incorporating MMR/MSI testing into the diagnostic workup of rare tumors such as GCA, particularly in young patients or those with a family history suggestive of Lynch syndrome, to optimize personalized treatment strategies.

Solitary pulmonary capillary hemangiomas (SPCHs) are recently recognized, rare benign lesions that form solitary nodules owing to capillary proliferation. These lesions are usually detected incidentally as small ground‐glass nodules (GGNs) on computed tomography (CT), and progressively enlarge over time. The radiological distinction from peripheral lung cancers is particularly challenging. However, to date, there have been no reports on progressive changes in the central density of SPCH on CT. An asymptomatic 49‐year‐old man was referred to our hospital for an abnormal shadow that was detected on chest CT during medical check‐up. He was subsequently followed‐up with chest CT. The nodule increased in size, and the central area became progressively denser. He underwent surgery 5 years and 10 months after the first visit owing to suspicion of lung cancer. Despite the collapse of the surgical specimen by artifacts, histopathological examination revealed a diagnosis of SPCH; collagenous fibers were found in the walls of the intralesional capillaries. The patient is presently alive without any recurrence, 6 months after the operation. In this case, the SPCH demonstrated a GGN with progressively increasing density of the central solid area on the CT. This remarkable feature made the preoperative distinction from lung cancer particularly difficult.

In intralobar pulmonary sequestrations, vascular changes similar to those in pulmonary hypertension (PH) are generally observed, such as intimal proliferation and plexiform lesions. However, to our knowledge, a sequestrated lung manifesting vascular changes with both arteritis and a plexiform lesion has never been reported. A 25-year-old man was diagnosed with intralobar pulmonary sequestration. Pathologically, both arteritis and a plexiform lesion were observed in the sequestrated lung. Systemic vasculitis syndrome was clinically excluded, and the pathological findings appeared to be associated with local PH. Arteritis is an extremely rare finding; only one case of arteritis associated with local PH has been reported in intralobar sequestration. In this case, the artery near the plexiform lesion had milder inflammation and fibrosis, suggesting that the arteritis formed prior to the plexiform lesion. This is the first case of arteritis and a plexiform lesion co-occurring in intralobar pulmonary sequestration associated with local PH. This case may shed light on the formation of plexiform lesions and their association with arteritis.

Carcinosarcomas with elements of cholangiocarcinoma and sarcoma are rare and have a poor prognosis. The spreading pattern and radiological findings of these lesions remain unclear. A 74-year-old man presented with a high γ-glutamyl transferase level. Magnetic resonance imaging revealed dilation of the right intrahepatic and common bile ducts, consistent with an intraductal papillary neoplasm of the bile duct (IPNB), and diffusion-weighted imaging (DWI) indicated an area of high signal intensity in the intrahepatic bile duct. Bile duct biopsy yielded a small amount of atypical spindle cells, and the patient underwent a right hepatectomy. Microscopically, the tumor contained cholangiocarcinoma and sarcomatous components, including osteosarcoma and leiomyosarcoma, leading to a diagnosis of intrahepatic carcinosarcoma. The tumor spread primarily through the intrahepatic bile duct. An accurate radiological diagnosis of carcinosarcoma was challenging, given the apparent similarities with IPNB. The findings from DWI and pathology of a bile duct biopsy may assist with preoperative diagnosis.

Metastatic diseases rarely develop in the colorectum, and diagnosing colorectal metastasis by biopsy without history of a malignant tumor or clinical information of a primary tumor is challenging. A 65-year-old woman with a 6-month history of constipation and diarrhea was admitted to our hospital and diagnosed with rectosigmoid colonic micropapillary carcinoma. Low anterior resection was performed after neoadjuvant chemotherapy. Because the lipoleiomyoma in the uterus obstructed the operator’s vision, total hysterectomy and bilateral salpingo-oophorectomy were performed. Examination of the colon and adnexa, together with immunohistochemical studies, revealed that the colonic tumor was actually serous carcinoma that had metastasized from the left fimbria of the fallopian tube. Retrospective immunohistochemical examination of the colon biopsy specimen suggested carcinoma with a Müllerian immunophenotype. When a colon biopsy reveals carcinoma with an invasive micropapillary pattern without a component of conventional tubular adenocarcinoma, immunohistochemical examination should be performed to rule out the possibility of metastasis.

The development of postoperative bronchopleural fistula (BPF) remains a challenge in thoracic surgery. We herein report a case of BPF successfully treated with endoscopic bronchial occlusion under computed tomography (CT) fluoroscopy and virtual bronchoscopic navigation (VBN). A 63-year-old man underwent right upper lobectomy with concomitant S6a subsegmentectomy for lung adenocarcinoma. On postoperative day 24, he complained of shaking chills with high fever. BPF with subsequent pneumonia and empyema. Despite aggressive surgical interventions for the BPF, air leakage persisted postoperatively. On days 26 and 34 after the final operation, endobronchial occlusions were performed under CT fluoroscopy and VBN. The air leaks greatly decreased and the patient was discharged. CT fluoroscopy and VBN can be useful techniques for endobronchial occlusion in the treatment of BPF.