Neuroendocrine Carcinoma Case Study
Clinical History
A 62 year old woman with a past history of breast cancer had been treated with a left mastectomy. She presented with weight loss, back pain and multiple cutaneous nodules along the trunk. An FDG PET•CT scan was requested for restaging.
Imaging Findings
Examination Protocol*:
Approximately 60 minutes following intravenous administration of 11.5 mCi of 18F FDG, a PET•CT scan was obtained from the base of the skull through the knees, and dedicated views of the head and neck. The CT portion of this study was a low dose, non-diagnostic and non-contrast CT, used for attenuation correction and anatomical localization only.
Imaging Findings:
Tomographic images of the head and neck showed extensive hypermetabolic bilateral upper, mid and lower cervical lymphadenopathy, as well as bilateral supraclavicular lymphadenopathy. Metastatic deposits in the medial end of the right clavicle (Fig. 1, upper row) and the left humeral head (Fig. 1, lower row) are also visualized. Multiple subcutaneous chest wall metastatic nodules are evident (Fig. 2, lower row and Fig. 3, upper row).
Images of the chest showed hypermetabolic bilateral axillary, extensive mediastinal, including pretracheal, subcarinal and bilateral hilar lymphadenopathy. A hypermetabolic right lower lobe lung nodule was noted. Multiple additional nodules were noted in both lungs on the CT scan which were not metabolically active. A left-sided pleural effusion was noted. In addition, multiple hypermetabolic subcutaneous nodules were noted, as well as right and left suprapectoral lymphadenopathy (Figs. 3-4).
Evaluation of the abdomen and pelvis showed multiple liver metastases, many displaying central necrosis. Multiple hypermetabolic mesenteric and retroperitoneal, as well as perirectal lymph nodes were noted. In addition, bilateral adrenal glands are involved with tumor. Multiple subcutaneous nodules were noted within the anterior abdomen as well as the back (Figs. 5-7).
The visualized portion of the skeletal system showed multiple metastases in the cervical, thoracic and lumbar spine, anterior and posterior ribs, the sternum, the left humeral head, the pelvis, and both femurs (Figs. 7-8).
Diagnosis
In view of the extensive metastatic disease, inconsistent with the usual presentation of breast carcinoma, a biopsy was ordered to review the histopathology of the metastatic deposits.
Pathology
A biopsy was performed to review the histopathology of the metastatic deposits. A nodule in upper outer quadrant of the left breast which was hypermetabolic on PET•CT and evident on physical examination was biopsied. The histopathology revealed a poorly differentiated neuroendocrine carcinoma involving adipose tissue and skeletal muscle.
Change in Patient Management
The PET•CT scan identified extensive metastatic disease, and led to the change of diagnosis from recurrent breast cancer to neuroendocrine carcinoma. The therapeutic plan in this case was changed to chemotherapy. A combination of paclitaxel, carboplatin and etoposide, has shown favorable results in poorly differentiated neuroendocrine carcinoma.
Discussion
The scan demonstrated extensive metastatic disease which was inconsistent with the usual presentation of breast cancer. This prompted the biopsy, which demonstrated histology consistent with poorly differentiated neuroendocrine carcinoma involving adipose tissue and skeletal muscle.
Poorly differentiated neuroendocrine carcinoma tumors account for around 10% of all neuroendocrine tumors. They are extremely aggressive with a high rate of cellular proliferation as well as vascular invasion. Most often these tumors arise along the gastrointestinal tract, usually from the pancreas (1). Liver and ovarian tumor origins are also reported. Sometimes the location of the primary tumor is undetermined. In this particular case however, no pancreatic mass was seen on the CT portion of the study. These tumors metastasize early. They are diagnosed histologically using immunohistochemical staining. As part of the dedifferentiation process, these tumors lose somatostatin expression. The sensitivity of octreotide imaging is thus decreased in this group of tumors. At the same time, however, their decreased differentiation and accelerated rate of proliferation results in increased glucose transport and metabolism. Consequently, FDG PET is highly sensitive for detection of this class of tumors. In addition, the degree of FDG uptake is a marker of prognosis; the higher the uptake the worse the prognosis (2). In one series (3) of 29 patients, the retroperitoneum, lymph nodes and mediastinum were the most frequently involved, with 17 of them having metastatic disease at two or more sites, and none showing evidence of hormone-related syndromes.
Data courtesy of Dr. Charles Intenzo and Dr. Sung Kim, Jefferson Center City Imaging, Philadelphia, PA
References:
1. Imaging pancreatic islet cell tumors – Power et al – Imaging 2002;14:147-159
2. The present and future roles of In-111 pentetreotide in the PET era – Rambaldi et al – QJ Nucl Med 2005;49(3):225-235
3. Poorly differentiated neuroendocrine carcinoma of unknown primary tumor site – Garrow et al – Seminars in Oncology 1993;20(3):287-291
* Any of the protocols presented herein are for informational purposes and are not meant to substitute for clinician judgment in