Differentiation between adrenocortical carcinoma and lipid-poor adrenal adenoma using a multiparametric MRI-based diagnostic algorithm.

PURPOSE: The purpose of this study was to evaluate the capabilities of multiparametric magnetic resonance imaging (MRI) in differentiating between lipid-poor adrenal adenoma (LPAA) and adrenocortical carcinoma (ACC). MATERIALS AND METHODS: Patients of two centers who underwent surgical resection of LPAA or ACC after multiparametric MRI were retrospectively included. A training cohort was used to build a diagnostic algorithm obtained through recursive partitioning based on multiparametric MRI variables, including apparent diffusion coefficient and chemical shift signal ratio (i.e., tumor signal intensity index). The diagnostic performances of the multiparametric MRI-based algorithm were evaluated using a validation cohort, alone first and then in association with adrenal tumor size using a cut-off of 4 cm. Performances of the diagnostic algorithm for the diagnosis of ACC vs. LPAA were calculated using pathology as the reference standard. RESULTS: Fifty-four patients (27 with LPAA and 27 with ACC; 37 women; mean age, 48.5 ± 13.3 [standard deviation (SD)] years) were used as the training cohort and 61 patients (24 with LPAA and 37 with ACC; 47 women; mean age, 49 ± 11.7 [SD] years) were used as the validation cohort. In the validation cohort, the diagnostic algorithm yielded best accuracy for the diagnosis of ACC vs. LPAA (75%; 46/61; 95% CI: 55-88) when used without lesion size. Best sensitivity was obtained with the association of the diagnostic algorithm with tumor size (96%; 23/24; 95% CI: 80-99). Best specificity was obtained with the diagnostic algorithm used alone (76%; 28/37; 95% CI: 60-87). CONCLUSION: A multiparametric MRI-based diagnostic algorithm that includes apparent diffusion coefficient and tumor signal intensity index helps discriminate between ACC and LPAA with high degrees of specificity and accuracy. The association of the multiparametric MRI-based diagnostic algorithm with adrenal lesion size helps maximize the sensitivity of multiparametric MRI for the diagnosis of ACC.

Brain tissue heterotopic in the adrenal gland in a child: a scarce case report.

Heterotopic brain tissue is rare and has not been reported. Our center made the first report. 4 years and 2 months old Girl presented with a cystic mass in the right adrenal gland 2 weeks after right upper abdominal pain. The operation was successful, and the diagnosis was confirmed by postoperative pathology. 6 months after the procedure, the incision healed well without recurrence. This case report has a detailed diagnosis and treatment process and satisfactory examination results. It can provide a reference for diagnosing and treating clinical HBT and reduce the risk of misdiagnosis and mistreatment.

Giant left pheochromocytoma with vascular anomalies and pelvic horseshoe kidney: a case report.

BACKGROUND: Pheochromocytoma is a neuroendocrine tumor, and its treatment is dependent on surgical resection. Due to the wide availability of cross-sectional imaging, pheochromocytomas are commonly seen as small tumors less than 10 cm in size and are mostly treated with minimally invasive surgery. Their concomitant presence with horseshoe kidney or other anatomical and vascular anomalies is rare. Herein, we present a surgically complex giant pheochromocytoma case who underwent an open left radical adrenalectomy. CASE PRESENTATION: A 41-year-old Hispanic female presented with a 12 × 8 cm left hypervascular adrenal mass, pelvic horseshoe kidney, and severely dilated large left retro-aortic renal vein which branched into a left adrenal vein, congested left ovarian vein, and left uterine plexus. She was managed with insulin and metformin for uncontrolled diabetes with an A1c level of 9% and doxazosin for persistent hypertension. Clinical diagnosis of pheochromocytoma was confirmed with elevated urine and serum metanephrine and normetanephrine. The pre-operative ACTH was within normal range with a normal dexamethasone suppression test and 24-hour urine free cortisol. The adrenalectomy of the highly aggressive adrenal mass was performed via open approach to obtain adequate surgical exposure. Due to the large size of the tumor and its significant involvement with multiple adjacent structures, coordination with multiple surgical teams and close hemodynamic monitoring by anesthesiology was required for successful patient outcomes including preservation of blood supply to the pelvic horseshoe kidney. The histopathological diagnosis was pheochromocytoma with negative surgical margins. The patient was followed at 1, 4, 12, and 24 weeks postoperatively. She had a normal postoperative eGFR and was able to discontinue antihypertensive and antidiabetic medications at four weeks. She had transient adrenal insufficiency, which resolved at five months. The horseshoe kidney was intact except for a minimal area of hypo-enhancement in the left superior renal moiety due to infarction, which was significantly improved at six months. CONCLUSION: Our patient had a giant pheochromocytoma with anatomical variations complicating an already surgically challenging procedure. Nonetheless, with multiple provider collaboration, detailed pre-operative surgical planning, and meticulous perioperative monitoring, radical resection of the giant pheochromocytoma was safe and feasible with successful postoperative outcomes.

Adrenal and juxta-adrenal schwannomas: A single-centre study.

OBJECTIVE: Adrenal schwannomas and juxta-adrenal schwannomas are rare tumours. We aimed to summarise their clinical, biochemical and imaging characteristics. DESIGN: Single-centre retrospective study of eligible patients between 1995 and 2022. PATIENTS AND MEASUREMENTS: Patients with a histopathologic diagnosis of adrenal or juxta-adrenal schwannoma. RESULTS: Twenty-four patients were diagnosed with either primary adrenal schwannoma (8, 33%) or juxta-adrenal schwannoma (16, 67%). Most tumours (21, 88%) were discovered incidentally on imaging. All tumours were unilateral, with 15 (62%) on the left and 9 (38%) on the right. At diagnosis, the median tumour size was 4 cm (range, 2-13 cm). Adrenal schwannomas were smaller when compared to juxta-adrenal schwannomas (median of 3.1 cm [range, 2-9 cm] vs. 4.6 cm [range, 2.3-13.3 cm], p = .037). On imaging, the tumours were round or oval in shape in 16 (70%), lobulated in 7 (30%), solid in 15 (68%), solid-cystic in 7 (32%), heterogeneous in 14 (61%) and homogeneous in 9 (39%). The median unenhanced computed tomography attenuation was 30 Hounsfield units (HU) (range, 12-38 HU). Of the 20 patients who underwent complete hormonal testing, all had nonfunctioning tumours. There was no recurrence or new tumour development in our cohort. CONCLUSIONS: Adrenal and juxta-adrenal schwannomas are nonfunctioning benign tumours that present with indeterminate radiographic features, including large tumour size and increased unenhanced CT attenuation. We did not find an imaging phenotype that was diagnostic of schwannoma. The diagnosis of this rare tumour is based on biopsy or resection.

Comparative Analysis of Laparoscopic and Robotic Transperitoneal Adrenalectomy Performed at a Single Institution.

Background and Objectives: Laparoscopic adrenalectomy (LA) is the standard surgical approach for adrenalectomy. At present, robotic adrenalectomy (RA) has been introduced at various hospitals. This study evaluated our initial experience with robotic adrenalectomy compared with conventional laparoscopic adrenalectomy. Materials and Methods: From October 2018 to March 2022, 56 adrenalectomies were performed by a single endocrine surgeon. Thirty-two patients underwent LA (LA group), and twenty-four patients underwent RA (RA group). Results: Patients in the RA group were significantly younger than those in the LA group (48.6 ± 9.7 years vs. 55.1 ± 11.4 years, p = 0.013). The RA group had a shorter operation time than the LA group (76.1 ± 28.2 min vs. 118.0 ± 54.3 min, p < 0.001). The length of hospital stay and postoperative pain level between the two groups were similar. There were no complications in the RA group. There was no significant difference in the pathologic diagnosis between the two groups. The cost of surgery was significantly higher in the RA group than in the LA group (5288.5 US dollars vs. 441.5 ± 136.8 US dollars, p < 0.001). Conclusions: In our initial experience, RA showed a shorter operation time than LA and no complications. RA could be a viable alternative surgical option for adrenalectomy, notwithstanding its higher cost.

Retroperitoneal tumor finally diagnosed as a bronchogenic cyst: A case report and review of literature.

BACKGROUND: Retroperitoneal bronchogenic cyst (RBC) is an extremely rare developmental abnormality. Most are benign tumors but malignant transformation is possible. Because of their anatomical position, RBCs are easily misdiagnosed as adrenal or pancreatic solid tumors on radiological evaluation. Here, we report a case of RBC, review the literature, and summarize some important features. CASE SUMMARY: A 49-year-old woman was incidentally found to have a retroperitoneal tumor during a physical examination. Enhanced computed tomography and laboratory evaluations, including routine blood examination, blood biochemistry, 24-h urine 17 ketones, 17 hydroxyls, adrenocortical hormone, serum potassium concentration, serum amylase, lipase, and epithelial tumor markers, revealed a moderate density, 54 mm × 40 mm mass with a clear boundary near the left adrenal gland. The were no abnormalities in the blood and urine values. Because the patient had a history of hypertension and the location of the mass was adjacent to the adrenal gland, it was initially diagnosed as a left adrenal tumor and was resected by retroperitoneal laparoscopy. However, the pathological examination after surgery confirmed it to be a bronchogenic cyst. CONCLUSION: Retroperitoneal laparoscopic surgery can be prioritized for symptomatic RBC patients. Conservative treatment is feasible for selected patients.

Robotic Adrenalectomy: A 10-Year Clinical Experience at a Tertiary Medical Center.

Background and Objective: Laparoscopic adrenalectomy is now the preferred approach for most adrenal tumors. As minimally invasive surgery departments gain familiarity with the robotic platform, the safety profiles and efficacy of robotic adrenalectomy has been an area of continued discussion. The objective of this study is to outline our experience with transitioning to the robotic platform and determining the effectiveness and safety of transperitoneal robotic adrenalectomy. Methods: We performed a single-center, retrospective review of 37 patients who underwent transperitoneal robotic adrenalectomy between August 1, 2010 and August 31, 2020. Outcomes included patient morbidity, hospital length of stay, operative time, estimated blood loss, gland volume, pathology, and postoperative complications. Results: Sixty-five percent of the total robotic adrenalectomies were of the left adrenal gland. The average operating room time was 213 minutes. The average gland volume was 71 cm3, estimated blood loss was 74 mL and length of stay was 1.4 days. There were no significant differences in outcomes between the right and left total robotic adrenalectomies. Approximately one-third of our cohort had an adrenal cortical adenoma, while only one patient had adrenal cortical carcinoma. Four patients experienced postoperative complications that resulted in unplanned hospital readmissions and there was one mortality. Conclusions: Although the standard of care for most adrenal tumors is laparoscopic resection, our 10-year experience has shown that robotic adrenalectomy is highly effective and can be a valuable tool in the community and academic setting.

Adrenal Castleman's Disease: Case Report and Review of Literature.

Castleman's disease is a rare lymphoproliferative disorder of poorly understood etiology. It is most commonly located in the mediastinum. Castleman's disease mimicking adrenal neoplasm is a very rare differential diagnosis and unusual presentation. We report a rare suprarenal unicentric hyaline vascular variant of the disease in a 16-year-old boy with atypical symptoms mimicking an adrenal neoplasm.

Adrenocortical carcinoma and a sporadic MEN1 mutation in a 3-year-old girl: a case report.

Childhood adrenocortical carcinoma (ACC) is a rare disease that is mostly linked to familial cancer syndrome. Although the prevalence of ACC is extremely low in children, it is clinically important to diagnose ACC early because age and tumor stage are closely related to prognosis. From this perspective, understanding the underlying genetics and possible symptoms of ACC is crucial in managing ACC with familial cancer syndromes. In this report, we present the case of a 3-year-old girl who initially presented with symptoms of precocious puberty and was later found to have ACC by imaging analysis. On genetic analysis, the patient was found to have a MEN1 gene mutation. MEN1 mutations are found in patients with multiple endocrine neoplasia type 1 (MEN1), usually precipitating multiple endocrine tumors, including pituitary adenoma, parathyroid hyperplasia, and adrenal tumors. Although MEN1 mutation is usually inherited in an autosomal dominant manner, neither of the patient's parents had the same mutation, making hers a case of sporadic MEN1 mutation with initial presentation of ACC. The clinical course and further investigations of this patient are discussed in detail in this report.

Analysis of etiology distribution and clinical manifestation in bilateral adrenal lesions / 中华内分泌外科杂志

Objective:To investigate the etiologies and clinical characteristics of bilateral adrenal lesions.Methods:The clinical data of 143 patients with bilateral adrenal lesions hospitalized in the First Affiliated Hospital of Chongqing Medical University from Jan. 2013 to Mar. 2018 were collected and analyzed.Results:140 patients were retained for final analysis. 79 were men, and 61 were women. The age was (51.53±13.93) years. Regarding the etiologies, there were primary aldosteronism ( n=44, 31.43%) , Cushing’s syndrome ( n=27, 19.29%) , non-functional lesions ( n=23, 16.43%) , adrenal tuberculosis ( n=17, 12.14%) , pheochromocytoma ( n=11, 7.86%) , congenital adrenal hyperplasia ( n=5, 3.57%) , adrenal metastases ( n=5, 3.57%) , and adrenal lymphoma ( n=4, 2.86) . These patients were classified into the following groups according to the mass size: ≤2 cm, 2-4 cm and ≥4 cm. The highest proportion of primary aldosteronism (62.79%) , Cushing’s syndrome (46.15%) and pheochromocytoma (31.25%) was observed in the ≤2 cm, 2-4 cm and ≥4 cm groups, respectively. The mass sizes of primary aldosteronism, Cushing’s syndrome and pheochromocytoma were compared, with pheochromocytoma the largest, followed by Cushing’s syndrome, non-functional lesion, and primary aldosteronism. Conclusions:For patients with bilateral adrenal lesions in our hospital, primary aldosteronism and Cushing’s syndrome are more common than non-functional lesion. Mass size is of great value in the diagnosis of endocrinological etiology, as well as distinguishing malignant tumors from the benign ones. The imaging phenotype is helpful to determine tumor types.

Adrenal-Renal Fusion with Adrenal Cortical Adenoma and Ectopic Adrenal Tissue, Presenting as Suspected Renal Mass: A Case Report.

Adrenal-renal fusion with adrenal cortical adenoma is a rare anomaly with only a few cases described in the literature. Imaging-based identification of this anomaly remains a diagnostic challenge, making it difficult to differentiate upper pole renal malignancy from adrenal cortical adenoma. We describe a case of a 62-year-old woman with an upper pole cystic renal mass on imaging, who underwent robotic partial nephrectomy. Intraoperatively the renal mass was found to be an adrenal-renal fusion anomaly, with ectopic adrenal tissue. Adrenal-renal infusion of an adrenal cortical adenoma was confirmed on final pathology. Due to lack of imaging-based diagnosis, this condition should be considered in the differential for upper pole renal masses.

[Surgery of adrenal diseases]. / Chirurgie der Nebennierenerkrankungen.

Incidentally discovered adrenal alterations should be separated into those without any clinical importance and adrenal diseases that have to be surgically or conservatively treated. Before operative treatment, in addition to the possible different functional activity of tumors, a differentiation must be made between sporadically arising singular or multiple adrenal tumors or nodular adrenal hyperplasia, adrenal tumors as part of a familial syndrome and metastases of other primary malignant tumors into the adrenal glands. Benign hormonally active adrenal tumors as well as questionable malignant tumors of the adrenal cortex are resected by minimally invasive techniques. For large malignant tumors infiltrating into surrounding tissues and tumors with proven lymph node metastases, the primarily open approach is indicated. Patients with adrenal diseases should always undergo an interdisciplinary assessment and in cases with clear indications for surgery, sometimes transferred to a center with experience in surgery and postoperative management of these patients.

Light-intensity Activity-related Nausea: An Unusual Presentation of Pheochromocytoma.

Pheochromocytomas are rare neuroendocrine tumors arising from chromaffin cells of the adrenal gland. Because of their highly variable clinical spectrum, these tumors often go undiagnosed and result in life-threatening complications. The typical presentations include episodic headache, palpitations and sweating accompanied with sustained or paroxysmal hypertension. However, less than half of pheochromocytoma patients have these classic symptoms. Many patients present with atypical symptoms, which could be overlooked. Our case represents an unusual presentation of pheochromocytoma, which is not well recognized as a possible manifestation. A 60-year-old woman presented with light-intensity-related nausea, which progressed to severe vomiting with hypovolemic shock. An unexpected adrenal mass was found during sonographic evaluation of the volume status. Pheochromocytoma was confirmed by 24-hour urine fractionated metanephrines and a computed tomography (CT) scan. In pheochromocytomas, the elevation of circulating catecholamines activates alpha-adrenergic receptors in the area postrema, which then initiates the emetic cascade. Light-intensity activity-related nausea and vomiting, especially when present with other symptoms of catecholamine excess, could be considered as a clinical presentation of pheochromocytomas.

Estrogen-secreting adrenocortical carcinoma.

Adrenocortical carcinoma is a rare type of endocrine malignancy with an annual incidence of approximately 1-2 cases per million. The majority of these tumors secrete cortisol, and a few secrete aldosterone or androgen. Estrogen-secreting adrenocortical carcinomas are extremely rare, irrespective of the secretion status of other adrenocortical hormones. Here, we report the case of a 53-year-old man with a cortisol and estrogen-secreting adrenocortical carcinoma. The patient presented with gynecomastia and abdominal discomfort. Radiological assessment revealed a tumor measuring 21×15.3×12 cm localized to the retroperitoneum. A hormonal evaluation revealed increased levels of estradiol, dehydroepiandrosterone sulfate, and cortisol. The patient underwent a right adrenalectomy, and the pathological examination revealed an adrenocortical carcinoma with a Weiss' score of 6. After surgery, he was treated with adjuvant radiotherapy. Twenty-one months after treatment, the patient remains alive with no evidence of recurrence.

Estrogen-secreting adrenocortical carcinoma / 영남의대학술지

Adrenocortical carcinoma is a rare type of endocrine malignancy with an annual incidence of approximately 1–2 cases per million. The majority of these tumors secrete cortisol, and a few secrete aldosterone or androgen. Estrogen-secreting adrenocortical carcinomas are extremely rare, irrespective of the secretion status of other adrenocortical hormones. Here, we report the case of a 53-year-old man with a cortisol and estrogen-secreting adrenocortical carcinoma. The patient presented with gynecomastia and abdominal discomfort. Radiological assessment revealed a tumor measuring 21×15.3×12 cm localized to the retroperitoneum. A hormonal evaluation revealed increased levels of estradiol, dehydroepiandrosterone sulfate, and cortisol. The patient underwent a right adrenalectomy, and the pathological examination revealed an adrenocortical carcinoma with a Weiss' score of 6. After surgery, he was treated with adjuvant radiotherapy. Twenty-one months after treatment, the patient remains alive with no evidence of recurrence.

Complete remission of metastatic pheochromocytoma in 123I-metaiodobenzylguanidine scintigraphy after a single session of 131I-metaiodobenzylguanidine therapy: a case report.

BACKGROUND: Pheochromocytomas are rare neuroendocrine tumors, with a malignancy frequency of approximately 10%. The treatment of malignant pheochromocytoma is palliative, and the traditional management strategy has limited efficacy. Furthermore, no clear criteria exist for the treatment of metastatic pheochromocytoma, especially for unresectable lesions. We report a case of complete remission of metastatic pheochromocytoma in 123I-metaiodobenzylguanidine (MIBG) scintigraphy after a single session of 131I-MIBG therapy. CASE PRESENTATION: A 61-year-old woman had a right adrenal grand tumor and lymph node metastasis on the hilum of the right kidney, both of which incorporated MIBG. After surgery, immunostaining of a tumor specimen showed expression of the tumor makers chromogranin and synaptophysin. One year postoperatively, abdominal computed tomography revealed a local recurrence and retroperitoneal lymph node swelling. The local recurrence was positive for MIBG uptake, whereas the swollen retroperitoneal lymph nodes were negative. She underwent surgery again, but the local recurrence was unresectable because of rigid adhesion to the surrounding tissue. Immunostaining of an intraoperatively extracted swollen retroperitoneal lymph node showed expression of tumor markers. The patient then underwent a single session of 131I-MIBG therapy (7.4 GBq, 200 mCi), after which the residual lesions no longer incorporated MIBG, and a complete response in 123I- metaiodobenzylguanidine (MIBG) scintigraphy was achieved. The 131I-MIBG treatment was repeated 6 months later. None of the lesions were positive for MIBG uptake. CONCLUSIONS: 131I-MIBG therapy efficaciously treats unresectable lesions that are positive for MIBG uptake.

Bilateral primary adrenal diffuse large B cell lymphoma without adrenal insufficiency: A case report and review of the literature.

Primary adrenal lymphoma (PAL) is an infrequent malignant tumor, occurring in the bilateral adrenal glands as a mass in the majority of cases. The current study presents a case of bilateral primary adrenal diffuse large B cell lymphoma in a 52-year-old female patient, who presented with abdominal pain in the left lumbar region for ~2 weeks. Abdominal ultrasound examination and computed tomography scanning revealed a mass of 132×119×101 mm on the left adrenal gland and a mass of 53×27 mm on the right adrenal gland. A percutaneous biopsy was performed and histopathological examination further confirmed this lesion as diffuse large B cell lymphoma. The present study highlights the importance of early diagnosis of PAL, and performs a literature review of the subject.

Adrenal cholangiocarcinoma: a case report and literature review / 中华泌尿外科杂志

Objective To discuss the clinical characteristics and pathologic features of adrenal cholangiocarcinoma.Methods We reported one extremely rare adrenal cholangiocarcinoma case and review the relative literature.A 71-year-old male was admitted with right adrenal mass for 2 months.Patient has been suffered from hypertension and controlled by oral drugs for ten years.Enhanced computerized tomography (CT) revealed a mass in right adrenal gland area,with the size of 7.1 cm × 6.8 cm × 4.4 cm and inhomogeneous enhancement in arterial phase.Adrenal functional examination showed no obvious abnormalities of serum catccholamine,supine RAAS,cortisol determination and rhythm and urine VMA detection.Results After medical preparation of phenoxybenzamine for 3 weeks preoperatively,the patient's blood pressure was maintained at 110-125/80-90 mmHg and with stuffy nose and ruddy nail bed.The patient's weight gained of 1kg than before.Retroperitoneal laparoscopic resection of right adrenal tumor was performed in general anesthesia.The tumor that related to the inferior vena cava and liver was successfully removed without any other damage.The operation time was 155 min and estimated blood volume was 50 ml.Perioperative blood pressure of patient was stable and recovery was well.According to clinical characteristic and pathological test and immunohistochemical results,patient was diagnosed with adrenal cholangiocarcinoma.Followed up for 15 months,no tumor recurrence and metastasis based on ultrasound examination and CT,and with normal blood pressure.Conclusions Adrenal cholangiocarcinoma was extremely rare type in the adrenal malignant tumors based on hepato-adrenal fusion histologically.This case constitutes a contribution for the knowledge of adrenal cholangiocarcinoma.The imaging findings were heterogeneous enhancement of soft tissue masses,and there was no obvious abnormality in adrenal functional examination.The retroperitoneal laparoscopic surgery is a treatment choice for this kind of patient.

Clinicopathologic characteristics and reticular fiber staining of adrenocortical carcinoma / 临床与实验病理学杂志

Purpose To analyse the clinicopathologic characteristics and reticular fiber staining of adrenocortical carcinoma (ACC).Methods The clinical,imaging,pathological data and reticular fiber staining of 20 cases with adrenocortical adenoma (ACA) and 16 cases with ACC were analyzed retrospectively.Results The median course of disease and maximum diameter of ACA were 21 months and 2.6 cm respectively,but ACC were 5 months and 9.5 cm respectively.9 cases with ACC were diagnosed with distant metastasis.Histologically,ACA cells arranged in nest-like and coarse trabecular forms with acidophilic or clear cytoplasm,unconspicuous nuclear atypia,and rare mitotic figures.The capsules,sinusoids and veins were uninvolved,and hemorrhage,necrosis and thick collagen fibers were infrequent.The Weiss score of all ACA was less than 2 (average =0.85 ± 0.81).ACC cells arranged in nest-like,coarse trabecular,cord-like,and diffuse structure with acidophilic cytoplasm,various nuclear atypia and atypical mitotic figures.The invasion of capsules,sinusoids and veins,hemorrhage and necrosis regions and thick collagen fibers were easily found.The Weiss score of all ACC was more than 3 (average =5.2 ±1.3).Immunohistochemical staining showed that vimentin,Syn,NSE,CK,CR,Melan-A and α-inhibin were expressed similarly between ACA and carcinoma (P ＞ 0.05).Reticular fiber staining revealed that the reticular fiber structures of ACA were unbroken,but ACC were destructed with various degrees of rupture,collapse,sparsity or disappearance (P ＜ 0.01).Conclusion ACC lacks characteristic immune phenotype,but increased diameter,distant metastasis,thick collagen fibers and destructed reticular fibrillar network are helpful in the diagnosis of ACC.

Pheochromocytoma in Old World Primates (Macaca mulatta and Chlorocebus aethiops).

Pheochromocytoma, a rarely reported adrenal gland neoplasm in Old World primates, was diagnosed in 5 rhesus macaques (Macaca mulatta) and 2 African green monkeys (Chlorocebus aethiops) from 3 research institutions. Age and sex were available for 6 primates. Two males and 4 females were affected, ranging in age from 9 to 31 years. All neoplasms were unilateral and, in the cases reporting the affected gland, 4 involved the right adrenal gland and 2 involved the left. Diagnosis was established by characteristic histologic features. Immunohistochemically, neoplastic cells in all cases expressed chromogranin A and met-enkephalin and were negative for melan-A and inhibin. Six of 7 tumors were positive for ß-endorphin. Pulmonary metastases were present in 2 rhesus macaques and portal vein invasion in 1 African green monkey. To the authors' knowledge, this is the first report of malignant pheochromocytoma in Old World primates.