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Masatoshi Iihara

Publications and source records attributed to Masatoshi Iihara.

10 recordsLinked to original sources
PubMed2006

Preoperative localization of pancreatic insulinoma by super selective arterial stimulation with venous sampling.

Although most insulinomas are small, they have been successfully detected by computed tomography and magnetic resonance imaging recently. However, preoperative localization of the insulinomas by arterial stimulation with venous sampling is crucial when they show atypical findings on these imaging modalities. We report a case of a large benign insulinoma located at the pancreatic tail; this tumor was diagnosed correctly by super selective arterial stimulation with venous sampling.

Aged↗
PubMed2005

Probability of axillary lymph node metastasis when sentinel lymph node biopsy is negative in women with clinically node negative breast cancer: a Bayesian approach.

BACKGROUND: Although sentinel lymph node biopsy(SLNB)is highly accurate in predicting axillary nodal status in patients with breast cancer, it has been shown that the procedure is associated with a few false negative results. The risk of leaving metastatic nodes behind in the axillary basin when SLNB is negative should be estimated for an individual patient if SLNB is performed to avoid conventional axillary lymph node dissection(ALND). METHODS: A retrospective analysis of 512 women with T1-3N0M0 breast cancer was conducted to derive a prevalence of nodal metastasis by T category as a pre-test(i.e., before SLNB)probability and to examine potential confounders on the relationship between T category and axillary nodal involvement. Probability of nodal metastasis when SLNB was negative was estimated by means of Bayes' theorem which incorporated the pre-test probability and sensitivity and specificity of SLNB. RESULTS: Axillary nodal metastasis was observed in 6.1% of T1a-b, 25.1% of T1c, 28.7% of T2, 35.0% of T3 tumors. Point estimates for the probability of nodal involvement when SLNB was negative ranged from 0.3-1.3% for T1a-b, 1.6-6.3% for T1c, 2.0-7.5% for T2, and 2.6-9.7% for T3 tumors with representative sensitivities of 80%, 85%, 90% and 95%, respectively. The risk may be higher when the tumor involves the upper outer quadrant of the breast, while it may be lower for an underweight woman. CONCLUSIONS: The probability of axillary lymph node metastasis when SLNB is negative can be estimated using a Bayesian approach. Presenting the probability to the patient may guide the decision of surgery without conventional ALND.

Adult↗
PubMed2005

[Diagnosis and surgical treatment of adrenal tumors].

Adrenal surgery is necessary for the management of functioning adrenal tumors, such as aldosterone-producing adenoma, cortisol-producing adenoma, and pheochromocytoma. The role of adrenal imaging in primary hyperaldosteronism is to separate the surgically resectable unilateral aldosteronoma from bilateral hyperplasia. Once the clinical diagnosis of primary hyperaldosteronism is confirmed, adrenal computed tomography (CT) with 3-mm sections should be the first imaging study. If the results of CT and NP-59 scintigraphy are equivocal, adrenal venous sampling is necessary. Cortisol-producing adrenocortical adenomas are seen as adrenal masses 2.5 cm or larger in diameter in CT scanning. When an adrenal mass measures more than 5 cm in diameter, a functioning adrenal carcinoma should be considered. Symptomatic pheochromocytomas are almost always 2 cm or larger. On MR scanning, pheochromocytomas are extremely bright on T2-weighted images. In patients with ectopic pheochromocytomas, 131I-MIBG scintigraphy should be mandatory. In the past decade, laparoscopic adrenalectomy has replaced open adrenalectomy as a standard operative procedure for benign adrenal tumors. Adrenal-sparing laparoscopic surgery has recently become a feasible option in patients with hereditary bilateral pheochromocytomas.

Adrenal Cortex Neoplasms↗
PubMed2004

[Diagnosis and treatment for adrenocortical carcinoma].

Adrenocortical carcinomas frequently hypersecrete multiple adrenocortical steroids and their precursors. CT scan and MRI usually demonstrate necrotic lesions or areas of calcification in this uncommon tumor. Therapy in patients with adrenocortical carcinoma is less satisfactory. Surgical excision is the primary mode of therapy. Up to the present, mitotane (o, p'-DDD) treatment combined with chemotherapy has been the only palliative measure for patients with nonresectable or extensively recurrent tumors.

Adrenal Cortex↗
PubMed2003

Adult-type ganglioneuroblastoma in the adrenal gland treated by a laparoscopic resection: report of a case.

A case of ganglioneuroblastoma in the adrenal gland of a 50-year-old man is reported. The patient was incidentally found to have a nonfunctioning tumor in the right adrenal gland. The tumor, measuring 4.5 cm, was successfully removed using laparoscopy. Histologically, the tumor was diagnosed to be a ganglioneuroblastoma. Immunohistochemically, a few MIB-1-positive cells and no S-100 protein-positive cells were observed. There has been no evidence of recurrence for 2.5 years to date after the operation. Adrenal ganglioneuroblastoma is extremely rare in adults, and only seven such cases have been previously reported in the literature.

Adrenal Gland Neoplasms↗
PubMed2003

Adrenal-preserving laparoscopic surgery in selected patients with bilateral adrenal tumors.

BACKGROUND: There have been few reports of laparoscopic adrenal-sparing surgery for bilateral adrenal tumors. We review our experience with this type of surgery with the aim of evaluating its feasibility and safety. METHODS: Over a 4-year period, we treated 9 patients with bilateral benign adrenal tumors. Seven patients had bilateral pheochromocytomas (MEN 2: 5, VHL: 1, sporadic: 1), and 2 patients had Cushing's syndrome caused by bilateral adrenocortical adenomas. Laparoscopic procedures were performed by a flank approach. The mean diameter of the tumors was 3.7 cm (range, 2.0-8.5 cm). RESULTS: All the tumors were removed laparoscopically. Four patients with hereditary pheochromocytomas underwent bilateral total adrenalectomy because of the large tumor size and multiplicity. The other 5 patients were treated successfully with preservation of adrenocortical function. In 4 of these 5 patients, the adrenal tumors were 3 cm or less in diameter. None of the patients experienced surgical complications. At a mean follow-up of 16 months (range, 4-40 months), none of the 5 patients who were treated by adrenal-sparing surgery required corticosteroid replacement. CONCLUSION: Laparoscopic surgery is feasible for the treatment of bilateral adrenal tumors. Adrenal-preserving laparoscopic surgery may be practicable for the removal of these tumors, if the tumor on either side is 3 cm or less in diameter; however, our follow up is short (mean, 16 months).

Adrenal Gland Neoplasms↗
PubMed2003

Recent advances in minimally invasive pancreatic surgery.

For curative resection of pancreatic endocrine tumours, minimally invasive methods of pancreatic surgery, such as laparoscopy, should be indicated only for benign tumours. Among these uncommon tumours, pancreatic insulinomas are mostly benign and solitary. Successful management of patients with insulinomas relies on accurate localization of the tumour and the use of appropriate surgical techniques. Because of the small size of these tumours, conventional intraoperative ultrasonography combined with palpation has been widely regarded as the best localization procedure. Because contact ultrasonography, a new technique for localization of pancreatic lesions, can be used laparoscopically, several surgeons have used laparoscopy not only for localization, but also for resection of insulinomas. In the era of minimally invasive surgery for benign pancreatic lesions, we attempted laparoscopic-focused exploration of the pancreas for resecting insulinomas based on preoperative localization. We describe the use of this technique for the detection and resection of insulinomas and the results obtained, with a review of previous reports.

Endosonography↗
PubMed2003

Cushing's syndrome due to bilateral adrenocortical adenomas with unique histological features.

Cushing's syndrome due to bilateral cortisol-secreting adenomas rarely occurs. We present a case of Cushing's syndrome due to bilateral adenomas. Both adenomas had distinct cell compositions, and were compared with emphasis on immunohistochemical and enzyme histochemical analysis for cytochrome P450(11beta) and 3beta-hydroxysteroid dehydrogenase (3betaHSD). A 37 year-old female was diagnosed with ACTH-independent Cushing's syndrome based on physical findings and hormonal evaluation. High-resolution CT scan showed bilateral adrenocortical adenomas and atrophied glands. 131I-methylnorcholesterol incorporation into both glands suggested both adenomas were functional. Clinical diagnosis prior to surgery was ACTH-independent Cushing's syndrome due to functioning bilateral adenomas. The left adrenal gland was totally resected, while the right one was partially resected by laparoscopic approach. Both adenomas were black on cut sections, and were comparatively evaluated by immunohistochemical and enzyme histochemical analysis for P450(11beta) and 3betaSD. The left adenoma was 1.6 cm in diameter and had a complex cellular composition and enzyme expression similar to that of primary pigmented nodular adrenocortical disease (PPNAD), while the right adenoma was 1.8 cm in diameter with compact cells typical of a solitary cortisol-producing adenoma. Adjacent bilateral adrenal cortex showed marked atrophy, but contained several micronodules. Serum cortisol levels, both at basal and after a low dodexamethasone, normalized thirteen months after surgery. In conclusion, the present case of Cushing's syndrome with bilateral adrenal adenomas demonstrated for the first time the simultaneous occurrence of two distinct adenomas, an ordinary cortisol-producing adenoma and a PPNAD-like adenoma. Further case reports of multiple adrenal adenomas should be well-analyzed to clarify whether the results from this case represent a new subgroup of ACTH-independent Cushing's syndrome.

Adrenal Cortex Diseases↗
PubMed2002

Minimally invasive endocrine surgery: laparoscopic resection of insulinomas.

Pancreatic insulinomas are mostly benign and solitary tumors. Successful management of patients with insulinoma relies on accurate localization of the tumors and the use of appropriate surgical techniques. However, preoperative radiological imaging studies often fail to localize the insulinomas because of the small tumor sizes. Conventional intraoperative ultrasonography combined with palpation has been widely used as the best localization tool. Since contact ultrasonography, a new technique for localizing pancreatic lesions, became available as a laparoscopic study, several surgeons have utilized laparoscopy for not only localization but also resection of insulinomas. Previous reports of laparoscopic ultrasonography for intraoperative identification of insulinomas showed a 100% success rate in cases with insulinoma localized by preoperative imaging studies, but a less satisfactory rate in cases with occult insulinoma. Laparoscopic resection of insulinomas located in the head of the pancreas is often difficult because of its anatomical relationship with important adjacent structures such as pancreatic duct and mesenteric vessels. In contrast, insulinomas located in the body or tail of the pancreas are laparoscopically resectable even when they are in close proximity to the major pancreatic duct. Laparoscopic procedure is a feasible technique with low morbidity for surgical management of insulinomas. Accurate preoperative localization is essential for safe performance of this minimally invasive procedure.

Endocrine Surgical Procedures↗