[A metastatic neuroendocrine tumor with exceptional outcome!]

Assessment of tumor growth in pancreatic neuroendocrine tumors in von Hippel Lindau syndrome

BACKGROUND

The incidence of pancreatic neuroendocrine tumors (PNETs) is increasing, but only a subset of these heterogeneous tumors will progress to malignant disease, which is associated with a poor prognosis. Currently, there are limited data on the natural history of these tumors and it is difficult to determine which patients require surgical intervention because the risk of metastatic disease cannot be accurately determined.

STUDY DESIGN

We conducted a prospective study of 87 patients with von Hippel Lindau syndrome-associated solid pancreatic lesions to determine the natural history of these tumors with biochemical testing, follow-up anatomic and functional imaging, and advanced imaging analysis, with a median follow-up of 4 years.

RESULTS

Approximately 20% of consecutive tumor measurements during follow-up were decreased in size and 20% showed no change. This included 2 of 4 surgically proven malignant tumors, which had a net decrease in tumor size over time. Tumor volume, as derived from greatest diameter and volumetric measurements, showed good correlation to pathology tumor measurement of surgically resected tumors (Spearman rank correlation ρ = 0.72, p = 0.0011, and ρ = 0.83, p < 0.0001, respectively). Tumor density measurement had an inverse relationship with tumor size (Spearman rank correlation -0.22, p = 0.0047). A tumor density cutoff of 200 was 75% specific for malignant tumors.

CONCLUSIONS

Pancreatic neuroendocrine tumors demonstrate a nonlinear growth pattern, which includes periods of no growth and apparent decrease in size by imaging. These growth patterns are variable and are not associated with tumor grade and malignancy. Tumor density, as measured in this cohort, may offer a specific diagnostic tool for malignant disease.

Complete spontaneous regression in Merkel cell carcinoma

Merkel cell carcinoma is a rare, aggressive, cutaneous malignancy of the elderly with a generally poor prognosis. Like all skin cancers, its incidence is rising. A few reports of spontaneous regression have been published. The case of a 67-year-old female patient who presented with a cheek Merkel cell carcinoma is described. Following biopsy it underwent complete regression with no evidence of residual tumour in the excision specimen taken seven weeks later. The current knowledge of Merkel cell carcinoma and the other cases of spontaneous regression described in the literature are reviewed.

Somatostatin analog therapy in treatment of gastrointestinal disorders and tumors

Long-acting octapeptide somatostatin analogs can effectively control symptoms resulting from excessive hormone release in patients with endocrine tumors of the gastrointestinal tract, provided that these tumors and metastases show a high expression of the somatostatin receptor subtype 2. The presence of this receptor subtype on these tumors can be demonstrated by in vitro studies, but also in vivo using 111In-pentetreotide scintigraphy. In a few studies, significant antiproliferative effects of these drugs on these tumors have also been demonstrated. The effectiveness of octapeptide somatostatin analogs in the management of chemotherapy- related and AIDS-related diarrhea and in reducing postoperative complications of pancreatic surgery have also been demonstrated. These drugs have been used to decrease the output of enterocutaneous pancreatic fistulas and are prophylactically used to prevent the development of these fistulas. Octapeptide somatostatin analog therapy is widely accepted for the initial management of acute variceal bleeding in cirrhotic patients. These drugs are currently also being evaluated for the treatment of advanced hepatocellular carcinoma and malignant intestinal obstruction. Radiotherapy with octapeptide somatostatin analogs coupled to radionuclides such as indium-111, yttrium-90, and lutetium- 177 is currently being studied in phase I-III trials.

[Neuroendocrine renal tumor. An unusual case. Review of the literature]

The neuroendocrine renal tumors are of extremely strange presentation. We present a review of the literature published on this pathology.