The patient was a 69-year-old man who was diagnosed with hypothyroidism associated with chronic thyroiditis 30 years previously and since then had been treated with levothyroxine sodium hydrate replacement therapy. A fine-needle aspiration cytology was performed for a nodule of the right lobe of thyroid which started to enlarge about 20 years previously, and he was referred to our hospital with a suspected diagnosis of follicular tumor, oxyphilic cell variant. A possibility of follicular carcinoma could not be ruled out by a neck echography. Accordingly, we decided to select surgery for diagnostic treatment, and performed right hemithyroidectomy. Histopathology revealed that the scattered tumor nests were characterized by epidermoid tumor cells with squamous differentiation and mucin-secreting cells, with parts of glandular structure. As we saw prominent eosinophilic leukocytes, lymphocytes, and plasmacytes infiltrating into fibrous stroma, sclerosing mucoepidermoid carcinoma with eosinophilia (SMECE) was diagnosed.

SMECE was first described by Chan et al in 1991. Although it is described as one of ‘other tumors, in the histological classification of thyroid tumors' in the 8^th Edition of General Rules for the Description of Thyroid Carcinoma, only 69 cases of SMECE have been reported so far. Herein we present this very rare case of SMECE with literature review.

A 54-year-old woman was injured in a two-vehicle traffic accident. At the time of contact with the ambulance crew, she was conscious and able to walk, but her left anterior chest became swollen over time, and a decrease in blood pressure was observed in the ambulance. On arrival at the hospital, marked swelling, tenderness, and subcutaneous hemorrhagic spots were observed at the left breast. She was in shock with a blood pressure of 73/36 mmHg, a pulse of 108 beats/min, and a respiratory rate of 27 beats/min. Contrast-enhanced computed tomography showed a giant hematoma and extravasation of contrast medium in her left breast, suggesting active bleeding from the left lateral thoracic artery branch. Considering the high risk associated with administering general anesthesia to a patient with unstable hemodynamics and the possibility that endovascular treatment might not reliably reach the bleeding point, the massive hematoma in front of the pectoralis major muscle was removed under local anesthesia, followed by application of gauze and compression fixation with an elastic bandage. She was decompressed the next day and found to have achieved hemostasis ; her drain was removed on postoperative day 6, and she was discharged the next day. Thus, a case of traumatic intramammary bleeding cured by hematoma removal and compression hemostasis under local anesthesia is reported.

Granulomatous mastitis is said to frequently occur at two to three years after childbirth and lactation. However, its onset during pregnancy is rarerly reported. Herein, we report a case of granulomatous mastitis diagnosed in early pregnancy that resolved with surgical treatment. A primiparous woman who was nine weeks and four days pregnant was diagnosed with mastitis at another hospital and was treated with antibiotics, but did not show improvement. She was then referred to our hospital. Histopathological examination showed granulomatous mastitis. Currently, there is no established treatment for granulomatous mastitis. Antibiotics, surgical treatment, such as incision and drainage, and steroid administration are often considered in many cases. However, since the patient was in the first trimester of pregnancy and drug treatment during early pregnancy is not recommended, surgery using the Seton method was performed and the patient has not relapsed even after childbirth.

An 82-year-old woman presented with a left breast mass and bleeding from the left breast. There was a breach in the integrity of the skin and an abscess. Surgical drainage was performed, and an antibiotic was administered. She underwent imaging to evaluate the breast when the inflammation had subsided. Ultrasonography showed a solid, 47-mm, cystic mass with an area of inflammation. Breast carcinoma was diagnosed based on a vacuum-assisted breast biopsy. The histopathological diagnosis was an encapsulated papillary carcinoma. When a breast abscess is seen in a relatively elderly woman over the age of 40 years, the possibility of breast cancer should be considered. The case of a patient with an encapsulated papillary carcinoma with a breast abscess is reported.

We present a case of a membranous tracheal injury caused by a single-lumen tube during thoracoscopic esophagectomy, which was repaired by thoracoscopic direct suture. The patient was a 45-year-old woman. She was diagnosed with cancer of the middle to lower thoracic esophagus and underwent thoracoscopic esophagectomy in a prone position under differential lung ventilation, using a single-lumen tube and a bronchial blocker catheter. During surgery, we identified a membranous tracheal injury. While we asked an anesthesiologist to precede with tracheal intubation keeping sufficient respiratory management, the injury was directly sutured under thoracoscopy and covered with a polyglycol acid sheet and fibrin glue. On the 6th hospital day, we confirmed that the injury was closed by a bronchoscope and the tube was removed on the 8th hospital day. On the 12th hospital day, she underwent exploratory laparotomy under general anesthesia for acute abdomen which was done under respiratory management, and no noteworthy adverse events were noted in the air passage. We must keep in mind that a tracheal injury can be caused even by manipulation for intubation by using a single-lumen tube and that the repair can be possible with sufficient respiratory management by working in closer cooperation with the anesthesiology department.

We have experienced two cases of contralateral pneumothorax during one-lung ventilation at pulmonary lobectomy. Case 1. An 82-year-old man developed hypoxemia during left upper lobectomy, triggered by a sealing test. Despite bronchoscopy performed to check the location of a tube and to aspirate sputum, no improvement was gained. A portable chest X-ray scan was performed, and right tension pneumothorax was observed and then improved with the insertion of a drain. Case 2. A 69-year-old man had prolonged hypoxia during left lower lobectomy, but the cause could not be identified. Postoperative portable chest X-ray showed right pneumothorax, and hypoxia was improved by insertion of a drain. We often encounter hypoxemia during surgery using a double-lumen tube. It can occur due to tube malposition, displacement, or tube occlusion from sputum secretion in many cases. Intraoperative contralateral pneumothorax is rare, but delayed diagnosis can be fatal. When intraoperative hypoxemia is observed without improvement by normal means, it is important to suspect contralateral pneumothorax first and respond promptly.

A 57-year-old woman presented to our hospital with dyspnea and chest pain of which she had been aware. A chest CT scan revealed an 18 × 13 cm chest wall tumor in the right thoracic cavity. CT-guided percutaneous needle biopsy led to a diagnosis of solitary fibrous tumor (SFT). It was difficult to differentiate whether the tumor was benign or malignant based on CT, MRI and FDG-PET findings. In December 2020, we performed thoracoscopic-assisted tumor excision. The histopathological study revealed patternless proliferation of spindle-shaped cells. The mitotic figure was 16/10HPF. Immunostaining studies showed CD34 positive and STAT6 positive. From these findings, we diagnosed the case as high-risk malignant SFT. The surgical stump was negative, indicating that a surgical complete resection could be achieved. No adjuvant chemotherapy was added, and the patient has been followed without any therapies.

Malignant SFT is an extremely rare entity, and its diagnostic criteria are still obscure. However, the risk of recurrence has been described in a variety of reports. We here present a case of SFT which was diagnosed as malignant and treated by surgical resection, with literature review.

A 46-year-old woman was referred to our department because a plain chest CT scan at another hospital incidentally revealed a mass lesion in the upper mediastinum. This was a rare imaging finding in which two tumors were present as if they sandwiched both the left common carotid artery and the subclavian artery from the anterior and posterior sides. The diagnosis of schwannoma was obtained by trans bronchial biopsy, and robotic-assisted surgery was indicated so that minimally invasive resection could be achieved, if they would remain as they were. On the cephalic side of the hemi-azygos vein, two ridging tumors were detected near the vagus nerve and were resected under the capsule while preserving the nerve. Another small tumor was found on the cranial side and resected in the same manner. Finally, these three tumors were determined to be linked up closely like a rosary. The pathological examinations showed all three tumors were schwannomas with no malignant findings. She had no skin lesions or auditory nerve tumors, and her family history of any neurogenic tumor was negative. The patient is now under observation with the diagnosis of multiple schwannomatosis. We report the case with a review of the literature.

This case involved a 75-year-old man who underwent mediastinoscopic subtotal esophagectomy, three-field lymph node dissection, retrosternal gastric tube reconstruction, and enterostomy for lower thoracic esophageal cancer. Enteral feeding was started through the enterostomy from post-operative day 1, and the dosage was gradually increased because anastomotic leakage occurred. On post-operative day 20, severe abdominal pain developed, and a contrast-enhanced computed tomography (CT) revealed portal venous gas and pneumatosis intestinalis. Since intestinal necrosis was suspected, the patient received emergent operation. There was no apparent evidence of ischemia, and the surgery was finished as exploratory laparotomy. Although enteral feeding was resumed on the fifth post-operative day, there was no recurrence, and the patient was discharged from the hospital. Portal venous gas and pneumatosis intestinalis associated with enteral feeding are rare complications and are not widely known in Japan. As we have encountered a case of portal venous gas and pneumatosis intestinalis following surgery for esophageal cancer, herein the case is reported with some bibliographical discussion.

A 48-year-old woman was referred to our hospital with the chief complaint of unbearable upper abdominal pain. Abdominal contrast-enhanced computed tomography showed a gastric wall abscess and possible minor gastric perforation. After conservative treatment, upper gastrointestinal endoscopy raised suspicion of a gastric aberrant pancreas with a wall abscess. However, the location was close to the pylorus, and the border of the abscess was unclear. Therefore, laparoscopy-assisted distal gastrectomy was performed. The postoperative pathological diagnosis was a wall abscess in an aberrant pancreas. Laparoscopy-assisted distal gastrectomy can be a feasible treatment for a symptomatic aberrant pancreas close to the pyloric ring.

A 72-year-old man who had previous histories of hypertension and chronic renal failure and had received a catheterization for heart failure one month before presented to our hospital with abdominal pain. There was tenderness in the entire abdomen and necrotic findings with pain affecting the bilateral toes. An abdominal CT scan showed intraabdominal free air. We performed emergency surgery with a diagnosis of diffuse peritonitis caused by gastrointestinal perforation. During surgery we detected multiple ulcers and a perforated portion in the small intestine. Partial resection of the small intestine was performed. The histopathological diagnosis was small bowel perforation caused by cholesterol crystal embolization. The patient was discharged from our hospital on the 21^st postoperative day, but he developed and died of gastrointestinal bleeding on the 49^th postoperative day.

Gastrointestinal perforation due to cholesterol crystal embolization is extremely rare and is reported to carry a poor prognosis. Although steroid therapy is reported to be effective in some cases, no effective therapies have been established. If it causes intestinal perforation, appropriate selection of surgical procedure and careful intraoperative management are important. We report a rare case of small bowel perforation caused by cholesterol crystal embolization with some literature review.

A 72-year-old man presented to our hospital with left lower abdominal pain. Physical examination revealed mild rebound tenderness in the left lower abdomen. Contrast-enhanced computed tomography revealed a hematoma with extravasation of the contrast agent in the left lower mesentery ; hemorrhagic ascites and a diverticulum from the descending to the sigmoid colon were also seen. We made a diagnosis of acute peritonitis with peritoneal hemorrhage caused by penetration of the diverticulum of the descending colon into the mesentery. Emergency laparotomy revealed hemorrhagic ascites and a hematoma in the mesentery near the descending colon. After intraperitoneal lavage, we resected the descending colon and mesentery with a hematoma approximately 10 cm in length, and performed a descending colonostomy. The resected specimen demonstrated a hematoma and rupture of the mesentery without intraluminal hemorrhage. We modified our diagnosis to intraperitoneal hemorrhage due to an arteriovenous malformation (AVM) because histopathological examination revealed arteriovenous irregularity and a shunt in the submucosa. AVMs are one of the causes of gastrointestinal bleeding, but intraperitoneal hemorrhage caused by AVM of the colon is rare. Therefore, we present our case with the relevant literature.

Leiomyomas of the mesentery are relatively uncommon, with few reports of mesenteric leiomyomas in the literature. A case of a mesenteric leiomyoma is presented. The patient, a 64-year-old man, had undergone surgery for rectal carcinoma one year earlier and was found to have a mesenteric tumor close to the inferior mesenteric artery on the postoperative follow-up. An FDG-PET scan showed hyperaccumulation in the tumor. Preoperatively, the diagnosis was a mesenteric tumor suspected as recurrence of rectal carcinoma. Subsequently, the patient underwent resection of the tumor. Histological examination of the tumor by hematoxylin and eosin staining showed a spindle cell tumor, and immunohistochemical studies were negative for c-kit and CD34, but positive for desmin. The final pathological diagnosis was mesenteric leiomyoma. The differential diagnosis of mesenteric leiomyoma and recurrence of rectal cancer can be challenging due to the similarity in imaging findings. This is a rare case of a mesenteric leiomyoma mimicking recurrence of rectal cancer.

A 77-year-old male visited our department with an anal mass. Digital examination revealed a protuberant tumor in the anal canal, and biopsy provided a diagnosis of mucinous adenocarcinoma. No obvious gross changes were observed on the perianal skin. The preoperative assessment was Stage I (T2N0M0). Laparoscopic abdominoperineal resection with D3 lymph node dissection was performed. As the tumor was a mucinous adenocarcinoma, the perianal skin was resected with a margin of approximately 3 cm from the anal verge. Pathological examination revealed the infiltration of Paget-like cells into the epidermis surrounding the tumor. Immunostaining revealed CK7- and CK20-positivity, and was negative for GCDFP-15 ; therefore, the patient was diagnosed with anal adenocarcinoma with pagetoid spread. The size of the pagetoid lesion that had spread to the anal side was 2 cm. No tumor cells were observed in the distal resection margins. The pathological assessment was stage IIIc (T3N2bM0). Postoperative adjuvant chemotherapy was administered, and the patient survived without recurrence. The possibility of pagetoid spread must be considered when treating cancers of the anal canal. It is important to secure sufficient resection margins, even if a preoperative diagnosis of pagetoid spread cannot be made due to poor perianal skin findings.

A 70-year-old woman had undergone laparoscopic liver cyst fenestration for a simple cyst in the right lobe of the liver. Seven months postoperatively, she developed bleeding from the hepatic cyst and was transferred to our hospital. The cyst was growing, and angiography showed contrast agent extravasation into the cyst from the peripheral side of the posterior segmental branch of the right hepatic artery. Preoperative computed tomography also showed signs of bleeding in the S8 hepatic dome and beneath the diaphragm, and embolization of the right hepatic artery peripheral to the cystic artery, A4, and the right subphrenic artery was conducted to embolize the arteries feeding the hepatic cyst as a whole. Seven hours later, the patient's blood pressure dropped rapidly, and it was considered that the embolization had been insufficient. Angiography was again performed, and coil embolization of the right hepatic artery was conducted, including the part as far as the cystic artery, after which hepatic cystectomy and cyst fenestration were performed. However, since recurrent cyst growth and progressive anemia were then observed, radical cystectomy was eventually performed. The patient is currently being monitored as an outpatient, and as of one year after the cystectomy, there has been no sign of recurrence. A rare case of a patient who developed delayed intracystic bleeding with hemorrhagic shock after hepatic cyst fenestration is reported.

Health insurance coverage for laparoscopic liver resection of all cases without revascularization or reconstruction of the biliary tract started in 2016 in Japan. Since then, the number of operations has increased. Recently, it was reported that laparoscopic surgery for patients who had a past history of liver resection was acceptable.

However, tumors located under the diaphragm (for example, segments 7 and 8) are difficult to access and require considerable experience and skill for safe resection. Moreover, it is difficult to access the transabdominal route for patients who have a history of abdominal surgery. The treatment results of video-assisted thoracoscopic surgery-hepatectomy (VATS-H) for a liver tumor located under the diaphragm are presented. VATS-H was useful for a liver tumor located under the diaphragm.

A 24-year-old man was brought to our hospital by ambulance complaining of severe right abdominal pain immediately after being kicked in the abdomen. Isolated gallbladder injury was diagnosed by contrast-enhanced abdominal computed tomography. Since contrast agent extravasation from the cystic artery was evident, emergency laparoscopic cholecystectomy was conducted. Although there was a subserosal hematoma around the neck of the gallbladder, there was no sign of perforation. The patient's postoperative course was generally good, and he was discharged on Day 7. Isolated gallbladder injury is extremely rare, and because it has no specific symptoms, its diagnosis and treatment are often very difficult. There have been very few reported cases of the use of laparoscopic surgery for gallbladder injury. A good outcome was achieved by diagnosis and treatment soon after the traumatic gallbladder injury was sustained. This case is reported along with a discussion of the literature.

A 53-year-old woman visited our department with the chief complaints of swelling in the right inguinal region. We diagnosed hydrocele of the canal of Nuck and performed hydrocelectomy. The histopathological diagnosis was endometriosis with a hydrocele of the canal of Nuck. Twenty-six months after the initial surgery, the abdominal contrast-enhanced computed tomography (CT) performed during follow-up of another disease incidentally revealed wall thickening from the ileum to the cecum. Laparoscopic ileocolic resection was performed for diagnostic and therapeutic purposes. The histopathological diagnosis was intestinal endometriosis. We retrospectively examined the abdominal plain CT images which were made prior to the initial surgery and found the thickening from the ileum to the cecum. This finding provided the evidence of coexisting hydrocele of the canal of Nuck and intestinal endometriosis. This suggests that preoperative and intraoperative intra-abdominal examination is important in the treatment of hydrocele of the canal of Nuck.

A 78-year-old man who had undergone McVay repair for bilateral inguinal hernias 14 years previously presented to our hospital with a right groin mass. Abdominal computed tomography (CT) showed that a part of the bladder had prolapsed caudal to the inguinal ligament and medial to the femoral vein. A diagnosis of femoral hernia involving the bladder was made, and a laparoscopic transabdominal preperitoneal repair procedure was performed. The laparoscopy also revealed that the bladder was inserted into the femoral ring. The preperitoneal space was dissected toward the space of Retzius to avoid damaging the bladder. Subsequently, with retraction of the hernial sac, the bladder was returned to its correct position. The postoperative course was good, and the patient was discharged from the hospital on the second postoperative day ; no recurrence or symptoms were noted at the 12-month follow-up. Most bladder hernias occur as direct inguinal hernias, and rarely develop as femoral ones. Preoperative diagnosis is often difficult, and bladder injury can occur due to the difficulties involved in reduction. We were able to safely repair the bladder using a laparoscopic procedure, although dissection along anatomical landmarks is important to prevent bladder injury in such cases.