Coexistence of Dense and Sparse Areas in the Longitudinal Smooth Muscle of the Anal Canal: Anatomical and Histological Analyses Inspired by Magnetic Resonance Images.

Magnetic resonance images of the anal canal show small, circular, low-intensity areas arranged in a row and a high-intensity area surrounding them internally and externally in the longitudinal muscle layer that cannot be explained by current anatomical findings. The purpose of this study was to elucidate the detailed structure of the longitudinal smooth muscle of the anal canal and to interpret the magnetic resonance image of the longitudinal muscle. Specimens for macroscopic anatomy and histology were obtained from six and seven cadavers, respectively. The histological nature of the longitudinal muscle was examined by staining serial transverse and coronal sections of the lateral wall of the anal canal with Masson's trichrome stain and using immunohistochemistry for smooth and skeletal muscle fibers. Dense and sparse areas of smooth muscle fibers coexisted in the longitudinal muscle layer. The dense areas formed columnar muscle bundles approximately 1.0-1.5 mm in diameter, and they continued from the longitudinal muscle bundles of the rectum. The columnar muscle bundles of the longitudinal anal muscle were internally and externally surrounded by sparsely arranged smooth muscle fibers that ran longitudinally. The coexistence of dense and sparse areas of smooth muscle fibers suggests that the structure of the smooth muscle is optimized for its function. This histological nature is probably reflected in the magnetic resonance image of the longitudinal muscle as the coexistence of low- and high-intensity areas. Clin. Anat. 33:619-626, 2020. © 2019 Wiley Periodicals, Inc.

Analysis of Deep Posterior Anal Fistulas by Magnetic Resonance Imaging: Site of Primary Abscess and Extension Patterns According to the Primary Abscess Depth.

OBJECTIVES: The aim of this study was to use magnetic resonance imaging (MRI) to elucidate the site and depth of the primary abscesses associated with deep posterior anal fistulas and their extension patterns. METHODS: We analyzed 176 consecutive patients with deep posterior anal fistulas and classified the fistulas according to whether the MRI-detected site of the primary abscess was at a superficial or a deep external anal sphincter (EAS) level. RESULTS: The distance between the anal center and the primary abscess center was significantly shorter than the length of the EAS and radius at an angle of 45°. In addition, deep posterior anal fistulas with primary abscesses located at the deep EAS level penetrated the EAS significantly more laterally and made external openings at a significantly more lateral site than when the primary abscess was located at a superficial EAS level. CONCLUSIONS: Primary abscesses associated with deep posterior anal fistulas are located in the posterior intersphincteric space or in the EAS muscle itself, not in Courtney's space, as had previously been claimed.

Rules for anal fistulas with scrotal extension.

OBJECTIVES: To evaluate the rules for anal fistulas with scrotal extension, in particular, whether a high transsphincteric or suprasphincteric fistula, of which internal openings are usually located posteriorly, would extend into the scrotum. METHODS: We retrospectively analyzed 446 consecutive male patients who underwent definitive anal fistula surgery. We compared fistulas with scrotal extension according to the location of the internal opening and divided them into anterior and posterior groups. RESULTS: Forty-six (82.1%) of the 56 anal fistulas with scrotal extension had anterior internal openings. After excluding recurrent fistulas, 42 (87.5%) of the 48 anal fistulas with scrotal extension had anterior internal openings. The relative risk of scrotal extension in the anterior group was 14.22 times higher than that in the posterior group (95% CI: 7.43-27.21; p<0.0001). After excluding recurrent fistulas, this relative risk rose to 18.67 (95% CI: 8.18-42.58), (p<0.0001). CONCLUSIONS: Anal fistulas with scrotal extension are mostly low transsphincteric or intersphincteric with anterior internal openings. High transsphincteric or suprasphincteric fistulas rarely extend into the scrotum, except in recurrent cases.

Lymphoepithelial cyst of the pancreas associated with elevated CA 19-9 levels.

An extremely rare case of a lymphoepithelial cyst associated with persistent elevation of serum carbohydrate antigen (CA) 19-9 levels is described. A 72-year-old man was incidentally found to have a cystic tumor in the uncus of the pancreas and to have a high serum CA 19-9 level. At 2-year follow up, the tumor size had gradually increased and the high CA 19-9 level persisted. Because the malignant potential of the tumor could not be ruled out, a laparotomy was performed. The tumor was excised from the pancreas. On pathological examination, the tumor was proven to be a lymphoepithelial cyst. After the operation, the patient's serum CA 19-9 level decreased to the normal range. Lymphoepithelial cysts of the pancreas are a rare, benign entity. They are true pancreatic cysts, characterized by a mature, keratinizing, squamous lining surrounded by lymphoid tissue. Because the treatment options and the prognosis of these entities are quite different from those of other cystic neoplasms of the pancreas, preoperative differential diagnosis is the main issue. Thus, although they are rare, lymphoepithelial cysts should be considered in the differential diagnosis of cystic tumors of the pancreas.

The role of prophylactic bilateral oophorectomy at the time of initial diagnosis of a unilateral ovarian metastasis in cases with colorectal adenocarcinoma.

BACKGROUND/AIMS: In cases with a macroscopic unilateral ovarian metastasis of colorectal adenocarcinoma, a clear therapeutic policy regarding a prophylactic bilateral oophorectomy is lacking. METHODOLOGY: Four cases of ovarian metastases of colorectal adenocarcinoma are presented. RESULTS: Case 1 is a 63-year-old with ascending colon carcinoma, Dukes' C, and right oophorectomy due to metachronous ovarian metastasis. Case 2 is a 28-year-old with transverse colon carcinoma, Dukes' D, and right oophorectomy due to synchronous ovarian metastasis. Case 3 is a 40-year-old with rectal carcinoma, Dukes' B, and right oophorectomy due to metachronous ovarian metastasis. Case 4 is a 32-year-old with rectal carcinoma, Dukes' D, and bilateral oophorectomy due to synchronous and metachronous ovarian metastases. Later, in cases 1 and 3, in which a unilateral ovary was preserved, ovarian metastases to the preserved ovary were found and caused severe clinical symptoms. However, by that time their general condition did not permit any additional laparotomy. CONCLUSIONS: Without other extensive metastases, if demonstrable diseases are found in a unilateral ovary, a prophylactic bilateral oophorectomy is recommended.

Synchronous mucosa-associated lymphoid tissue lymphoma and gastrointestinal stromal tumor of the stomach presenting with gastric bleeding.

We report an extraordinarily rare case of synchronous mucosa-associated lymphoid tissue lymphoma and gastrointestinal stromal tumor of the stomach. An 80-year-old man presented with gastric bleeding. Gastroscopy showed an ulcerative lesion and a submucosal tumor at the upper corpus of the stomach. The ulcerative lesion was proven by biopsy to be mucosa-associated lymphoid tissue lymphoma, but the submucosal tumor could not be diagnosed. Due to the repeating episodes of massive gastric bleeding, a total gastrectomy with lymphadenectomy was performed. After the operation, the submucosal tumor was pathologically proven to be a gastrointestinal stromal tumor. In this case, synchronous occurrence of mucosa-associated lymphoid tissue lymphoma and gastrointestinal stromal tumor seems to be coincidental rather than related with the same pathogenic triggering. Surgical resection of the stomach provided an accurate diagnosis and an effective treatment.

Successful sphincter-sparing local excision for mucinous adenocarcinoma associated with chronic fistula in ano using preoperative MRI evaluation.

A 78-year-old man with a 10-year history of ischiorectal abscess was referred to our hospital because purulent drainage from an external opening changed to mucoid drainage. By the brushing cytology of fistula ano, mucinous adenocarcinoma was found. T2-weighted magnetic resonance imaging (MRI) indicated that a mucinous adenocarcinoma was localized within the abscess and the fistula, and was not invasive neoplasm. He underwent a sphincter-sparing local excision of the ischiorectal abscess including the fistula and openings. The pathological findings indicated that mucinous adenocarcinoma arose from anal glands, developed lining the preexisting abscess and fistula wall. Five years after the resection, he remains asymptomatic and free of disease. From the present case, it is advisable that a high index of clinical suspicion in any elderly patient presenting with perirectal abscess and a major impact of the MRI evaluation on the perioperative assessment of perianal diseases should be emphasized.

Successfully-treated mesenteric non-Hodgkin's lymphoma involving hepatic mass--a case report.

A mesenteric diffuse large B-cell lymphoma which also involves the liver is very rare. We describe herein a mesenteric diffuse large B-cell lymphoma with hepatic involvement successfully treated by the combination of surgical resection and multiagent chemotherapy. A 77-year-old man was referred to our hospital because of a right lower abdominal tumor. Abdominal computed tomography showed a mass in the mesenterium at the ileocoecal region and multiple mass in the liver. Gallium scintigram showed focal hot uptake at the ileocoecal region and multiple areas of increased Gallium uptake in the liver. With the diagnosis of a mesenteric tumor with liver metastases, a laparotomy was performed. By an intraoperative pathological examination, non-Hodgkin's lymphoma was suggested. The mesenteric mass was completely resected, but additional operative procedures were not done to the liver. After the operation, the patient was determined to have Stage IVB diffuse large B-cell lymphoma, and chemotherapy based on the CHOP-like regimen was given. After the 8th course of such chemotherapy, he was confirmed to have achieved a complete remission by abdominal computed tomography and Gallium scintigram.The Stage IV mesenteric diffuse large B-cell lymphoma involving the liver seems to be an indication for combination therapy of surgical resection and multiagent chemotherapy.

Huge pseudocyst of the pancreas caused by poorly differentiated invasive ductal adenocarcinoma with osteoclast-like giant cells: report of a case.

A 72-year-old man presented with several week's abdominal distension and jaundice. Under the tentative diagnosis of pancreatic pseudocyst of 22cm in diameter, a percutaneous drainage was performed. Despite the reduction of the pseudocyst, his serum total bilirubin level was increased. At this time, abdominal computed tomography scan showed a tumor at the uncinate process of the pancreas. After the biliary decompression, a total pancreatectomy with the resection of pseudocyst walls and splenectomy was performed. It was histologically proven to be poorly differentiated ductal adenocarcinoma in combination with osteoclast-like giant cells. The pseudocyst was considered to be due to the stenosis of the main pancreatic duct caused by carcinoma of the uncinate process. Five months later, he died of recurrent carcinomatous peritonitis. Osteoclast-like giant cell tumor is a very rare neoplasm, the origin and prognosis of which still remain obscure. However, it has to be considered in the differential diagnosis of cystic changes of the pancreas, especially of pseudocyst. Furthermore, detailed surveys are needed in cases of pseudocyst of the pancreas without chronic pancreatitis, in order to identify small carcinoma of the pancreas.

Histological features of human papilloma virus 16 and its association with the development and progression of anal squamous cell carcinoma.

PURPOSE: To investigate the development of anal squamous cell carcinoma (SCC) and the expression patterns of human papillomavirus (HPV). METHODS: We performed typing of HPV-DNA using a polymerase chain reaction (PCR), and amplified the Duchenne muscular dystrophy (DMD) genes simultaneously, to investigate the tumor DNA state. The expression patterns of HPV in the cancer cell nuclei was investigated by in situ hybridization (ISH) using HPV probes. RESULTS: Amplification of DMD genes was confirmed in 8 of 20 patients with anal SCC, suggesting that tumor DNA was preserved in these patients. In seven of these eight patients, only HPV16 was detected by both PCR and ISH, suggesting HPV16-induced carcinogenesis. In two patients with carcinoma in situ (CIS), the cancer cells showed only a diffuse pattern (DP), and in two patients with invasive cancer, the cancer cell showed only an oligo-dot pattern (OP). In one patient with lesions ranging from CIS to invasive cancer, the histologic features varied in each area, from DP to OP. This change originated in the deep part of the microinvasive area. CONCLUSIONS: These findings show that HPV16 infection is closely involved in the development of anal SCC and suggest that the change in the genome occurs at the stage of microinvasive cancer.

Nonfunctioning pancreatic endocrine tumor presenting with hemorrhage from isolated gastric varices.

Hemorrhage from gastric varices due to left-sided portal hypertension is an unusual presentation for pancreatic endocrine tumor. A case of pancreatic endocrine tumor presenting with gastric variceal hemorrhage secondary to left-sided portal hypertension associated with splenic vein occlusion is presented. A 53-year-old man with hemorrhage from isolated gastric varices was referred to our hospital. Laboratory studies revealed normal liver function. Surveys to identify the cause of gastric varices by an abdominal CT, MRCP, and abdominal angiography revealed splenic vein occlusion secondarily attributed to the pancreatic tail tumor and splenomegaly. The pancreatic tumor was suspected to be a resectable endocrine tumor. A distal pancreatectomy, splenectomy, partial resection of the gastric fundus, and limited lymph node dissection were performed. By the histological examination, the diagnosis of nonfunctioning pancreatic endocrine tumor with malignant potential was determined. Three years after the surgery, the patient is doing well and reveals no sign of recurrence. In this case, the unusual presentation for pancreatic endocrine tumors such as a gastric variceal hemorrhage had an advantage that led to early presentation prior to the development of metastases with possible curative surgery.

[Postoperative adjuvant immunochemotherapy using Lentinan for advanced gastric carcinoma patients with metastasis in the regional lymph nodes and serosal invasion].

Six patients with gastric cancer, stage IIIA to IV, received intraabdominal cisplatin (CDDP) at laporotomy. This was followed by postoperative intravenous infusion of mitomycin C (MMC), CDDP or fluorouracil (5-FU). When these patients recovered to the extent that permitted oral medication, an immunochemotherapeutic regimen containing either oral UFT (uracil and tegafur) or 5'-deoxy-5-fluorouridine (5'-DFUR), plus intravenous Lentinan (LNT) was administered for a period ranging from one and a half to two years. This postoperative immunochemotherapy was successful in all 6 patients. No relapse has been observed in any of them for at least 4 years. These findings indicate that the chemotherapeutic strategy of administering intraabdominal CDDP immediately after surgery, followed by postoperative immunochemotherapy with pyrimidine-fluoride products plus Lentinan on an outpatient basis may be useful in the treatment of T3 or T4 gastric carcinoma with metastasis in the regional lymph nodes.