Breast Carcinoma With Unrecognized Neuroendocrine Differentiation Metastasizing to the Pancreas: A Potential Diagnostic Pitfall

Metastatic breast cancer simulating well-differentiated neuroendocrine neoplasms of visceral organs

A series of metastatic breast carcinoma (MBC) mimicking visceral well-differentiated neuroendocrine neoplasms has not previously been reported. We identified 5 consultation cases originally submitted as neuroendocrine neoplasms in women but that were found to be MBC on subsequent review. All 5 neoplasms demonstrated nested architecture and relatively uniform nuclei. Four patients had a known history of breast cancer (remote in 3 and concurrent in 1), but the metastases (3 liver, 1 lung) labeled for chromogranin and/or synaptophysin, prompting misdiagnosis as neuroendocrine neoplasm. In a fifth case, a liver metastasis in a patient with a known pancreatic endocrine neoplasm was originally thought to be of pancreatic origin; an occult concurrent primary breast cancer (PBC) was subsequently identified as the source. On further immunohistochemistry (IHC), all metastases evaluated were diffusely, strongly positive for estrogen receptor (5/5 cases) and GATA3 (4/4 cases). Three patients had previously received ineffective treatment for neuroendocrine carcinoma. Based on the consultation diagnosis, all 4 patients with follow-up received hormone therapy, which was effective in 3. In a separate tissue microarray cohort of paired PBCs and hematogenous MBCs, chromogranin and/or synaptophysin IHC labeling was typically negative and increased from the PBC to the MBC in only 5% of cases. In conclusion, although neuroendocrine differentiation is uncommon in breast cancer and does not commonly increase in metastases, MBC with neuroendocrine differentiation should be considered in patients with visceral neuroendocrine neoplasms of unknown primary site. Diffuse IHC labeling for estrogen receptor and GATA3 helps establish the correct diagnosis.

Prospective evaluation of EUS-guided fine needle biopsy in pancreatic mass lesions

BACKGROUND AND STUDY AIM

Due to the scarcity of specific data on endoscopic ultrasound (EUS)-guided fine-needle biopsies (SharkCore) FNB in the evaluation of pancreatic lesions, we performed a prospective study of the diagnostic performance of EUS SharkCore FNB in patients with pancreatic lesions. The aim of this study was to evaluate the diagnostic accuracy.

PATIENTS AND METHODS

Single-center prospective study of 41 consecutive patients referred for EUS-FNB from October 2015 to April 2016 at our center. EUS-FNB was obtained in a predefined setting regarding the procedure and pathological evaluation. Data regarding demographics, lesion, technical parameters, and diagnostic accuracy were obtained.

RESULTS

The study included 41 consecutive patients (22 males (54 %); median age 68 years). The average size of the lesions was 28 mm (median: 30 mm). A diagnostic specimen was identified in 40 (98 %) cases during microscopy with an average of 2.4 passes. The route was trans-duodenal in 20 cases (49 %). The histological diagnosis of the specimens was malignant in 29 cases (71 %), benign in 8 (20 %), suspicious in 2 (5 %), atypical in 1 (2 %) and in 1 (2 %) no material for microscopic evaluation was obtained. This led to a diagnostic accuracy of 93 %, sensitivity of 91 % and a specificity of 100 %. 2 cases (5 %) of self-limiting bleeding were observed. The diagnosis at follow up was malignant in 32 (78 %) of the patients.

CONCLUSIONS

EUS-FNB of pancreatic mass lesions with the SharkCore needle produced specimens with a diagnostic accuracy of 93 %. The procedure was safe and easy to perform, and these data support the use of EUS-FNB in a routine setting.

Microscopic findings in EUS-guided fine needle (SharkCore) biopsies with type 1 and type 2 autoimmune pancreatitis

The International Consensus Diagnostic Criteria (ICDC) for the diagnosis of autoimmune pancreatitis (AIP) include the histological criterion that is based on either pancreatic core needle biopsies (CNBs) or surgical specimens. However, CNBs are difficult to obtain by endoscopic ultrasound (EUS). EUS fine-needle aspiration (EUS-FNA) cytology is usually not sufficient for the diagnosis of AIP, but may sometimes contain tissue microfragments. Another approach is EUS-guided histological fine-needle biopsy (EUS-FNB), using needles such as the SharkCore or ProCore needle. Published data regarding EUS-guided SharkCore FNB for the diagnosis of AIP are lacking. We aimed to describe our histological findings in one type 1 and two type 2 AIP patients who underwent EUS SharkCore FNB. The EUS-FNBs of two patients fulfilled the histological level 2 ICDC for type 1 AIP or type 2 AIP. The EUS-FNB of one patient fulfilled the histological level 1 ICDC for type 2 AIP. The tissue cylinders and fragments measured 55, 28 and 17 mm in total. At least histological level 2 ICDC were fulfilled in all cases, and our findings regarding the utility of EUS SharkCore FNB for the diagnosis of AIP are therefore promising, but further studies based on larger numbers of patients are warranted.