Imaging features of extrapulmonary small cell carcinoma

PET-CT in Clinical Adult Oncology: II. Primary Thoracic and Breast Malignancies

Simple Summary

Positron emission tomography (PET), typically combined with computed tomography (CT), has become a critical advanced imaging technique in oncology. With PET-CT, a radioactive molecule (radiotracer) is injected in the bloodstream and localizes to sites of tumor because of specific cellular features of the tumor that accumulate the targeting radiotracer. The CT scan, performed at the same time, provides information to facilitate assessment of the amount of radioactivity from deep or dense structures, and to provide detailed anatomic information. PET-CT has a variety of applications in oncology, including staging, therapeutic response assessment, restaging, and surveillance. This series of six review articles provides an overview of the value, applications, and imaging and interpretive strategies of PET-CT in the more common adult malignancies. The second article in this series addresses the use of PET-CT in breast cancer and other primary thoracic malignancies.

Abstract

Positron emission tomography combined with x-ray computed tomography (PET-CT) is an advanced imaging modality with oncologic applications that include staging, therapy assessment, restaging, and surveillance. This six-part series of review articles provides practical information to providers and imaging professionals regarding the best use of PET-CT for the more common adult malignancies. The second article of this series addresses primary thoracic malignancy and breast cancer. For primary thoracic malignancy, the focus will be on lung cancer, malignant pleural mesothelioma, thymoma, and thymic carcinoma, with an emphasis on the use of FDG PET-CT. For breast cancer, the various histologic subtypes will be addressed, and will include ¹⁸F fluorodeoxyglucose (FDG), recently Food and Drug Administration (FDA)-approved ¹⁸F-fluoroestradiol (FES), and ¹⁸F sodium fluoride (NaF). The pitfalls and nuances of PET-CT in breast and primary thoracic malignancies and the imaging features that distinguish between subcategories of these tumors are addressed. This review will serve as a resource for the appropriate roles and limitations of PET-CT in the clinical management of patients with breast and primary thoracic malignancies for healthcare professionals caring for adult patients with these cancers. It also serves as a practical guide for imaging providers, including radiologists, nuclear medicine physicians, and their trainees.

Collision tumor of small cell carcinoma and squamous cell carcinoma of the maxillary sinus: Case report

A collision tumor refers to the coexistence of two diagnostically distinct tumors in a common anatomic space. Collision tumors are rare in the oral and maxillofacial region. The present study reported on the case of an 82-year-old female with a collision tumor in the maxillary sinus consisting of small cell carcinoma (SmCC) and squamous cell carcinoma (SCC). Computed tomography (CT) imaging revealed a mass in the right maxillary sinus. The lesion exhibited heterogeneous low signal intensity (SI) on T1-weighted imaging (T1WI), high SI on short T1 inversion recovery and heterogeneous solid enhancement on contrast-enhanced T1WI. The histopathology result of a biopsy specimen confirmed SmCC. After the patient received a course of chemoradiotherapy, follow-up CT revealed a residual tumor. In a second surgery, a remaining tumor and histopathology revealed SCC with no evidence of SmCC. The final diagnosis was a collision tumor made up of SCC and SmCC.

Case of metastatic small cell carcinoma of the oropharynx successfully treated with image-guided volumetric modulated arc therapy (IG-VMAT): pushing the limits of technology to match treatment intent

Extrapulmonary small cell carcinomas (EPSCC) are a rare subtype of neuroendocrine tumours which have been documented to arise from a multitude of sites and treatment outcomes are disappointing. The most common site involved in the head and neck region is the larynx and the oropharynx as a primary site has been infrequently reported. The patient presented with bilateral neck swelling and an ulcerated lesion was noted in the base of tongue (BOT). A biopsy revealed small cell carcinoma (SCC) and was confirmed with immunohistochemistry. The final diagnosis after workup was SCC of BOT stage IVc. He received induction chemotherapy to which the tumour responded partially, followed by curative intent chemoradiotherapy and adjuvant chemotherapy. The patient achieved a radiological complete response to treatment and almost all treatment-induced toxicities resolved. An aggressive approach to managing EPSCC is possible with modern radiotherapy techniques, with tolerable treatment-induced toxicities.

Small cell carcinoma of the stomach: A report of two cases and a review of the literature

Primary small cell gastric carcinomas (SCGC) are rare tumors with an aggressive nature, characterized by early, widespread metastases and poor overall prognosis. SCGC shares similar clinicopathological and molecular characteristics with small cell lung carcinoma and is usually treated in a similar manner. Here, two cases of SCGC in young Caucasian male patients are presented. One patient had metastatic and the other locoregional disease. Multimodal treatment was applied in each case; the resulting survival time was 20.2 months in the patient with initially locoregional disease whereas the remains alive and disease-free 20 months after initial diagnosis. A review of the literature is also presented.

Comparative study of lung and extrapulmonary poorly differentiated neuroendocrine carcinomas: A SEER database analysis of 162,983 cases

BACKGROUND

Extrapulmonary neuroendocrine carcinomas (NECs) are poorly studied and are managed similar to lung NECs, which may not account for differences between the 2 groups of tumors as well as the heterogeneity within extrapulmonary NEC.

METHODS

Data from the Surveillance, Epidemiology, and End Results program between 1973 and 2012 were used to estimate the relative percentages of lung NECs and subgroups of extrapulmonary NECs, epidemiological patterns at these sites, and the median and 5-year overall survival rates.

RESULTS

Of 162,983 NEC cases, 14,732 were extrapulmonary; of these, 5509 were gastrointestinal (37.44%), 4151 were of unknown primary (28.2%), and 5072 were of other sites (34.4%). Lung NEC had the highest percentage of small cell morphology (95.2%) and gastrointestinal NEC had the least (38.7%), with the rest being other morphologies. Significant differences were noted with regard to median age (range, 48-74 years), percentage of cases of distant stage disease (24%-77%), and incidence according to sex and race. The median survival of patients with lung NEC was 7.6 months, that for patients with gastrointestinal NEC was 7.5 months (range, 25.1 months for NEC at the small intestine to 5.7 months for NEC at the pancreas), and that for patients with unknown NEC was 2.5 months. The 5-year survival rate for patients with local stage disease ranged from 58% to 60% for NECs of the female genital tract and small intestine to 25% for esophageal NECs. The primary tumor site remained statistically significant for survival even after adjusting for known prognostic variables (P<.0001).

CONCLUSIONS

To the authors' knowledge, the current study is the largest study of NECs performed to date and also the first with comprehensive epidemiological data. Significant differences in incidence patterns and large variations in survival depending on anatomical site and morphological subtype were noted. A curative approach is possible for patients with nonmetastatic NECs. Cancer 2018;124:807-15. © 2017 American Cancer Society.

PET/CT imaging in lung cancer: indications and findings

The use of PET/CT imaging in the work-up and management of patients with lung cancer has greatly increased in recent decades. The ability to combine functional and anatomical information has equipped PET/CT to look into various aspects of lung cancer, allowing more precise disease staging and providing useful data during the characterization of indeterminate pulmonary nodules. In addition, the accuracy of PET/CT has been shown to be greater than is that of conventional modalities in some scenarios, making PET/CT a valuable noninvasive method for the investigation of lung cancer. However, the interpretation of PET/CT findings presents numerous pitfalls and potential confounders. Therefore, it is imperative for pulmonologists and radiologists to familiarize themselves with the most relevant indications for and limitations of PET/CT, seeking to protect their patients from unnecessary radiation exposure and inappropriate treatment. This review article aimed to summarize the basic principles, indications, cancer staging considerations, and future applications related to the use of PET/CT in lung cancer.

High-Grade Neuroendocrine Colorectal Carcinomas: A Retrospective Study of 100 Patients

BACKGROUND

Colorectal high-grade neuroendocrine carcinomas (HGNEC) are a rare but aggressive group of malignancies without standard management recommendations.

METHODS

We retrospectively reviewed the records of 100 consecutive patients with histologically confirmed colorectal HGNEC diagnosed at MD Anderson Cancer Center between 1991 and 2013.

RESULTS

In our cohort, most tumors (89%) were small cell carcinoma, and most (60%) involved the sigmoid or the anorectal regions. Sixty-four patients (64%) presented with metastatic disease at diagnosis. Striking epidemiological and clinical differences between those established in small cell lung cancer (SCLC) and our cohort were noted, including significantly lower rates of smoking and lower risk of bone, brain metastases. Over 30% of the tumors were found associated with an adenoma. Median overall survival (OS) of the cohort was 14.7 months, with 2-year and 5-year OS rates of 23% and 8%, respectively. In patients with localized disease, multimodality therapy was associated with a trend toward improved median OS (20.4 vs. 15.4 months; P = .08). Metastases at presentation (OS 20.63 vs. 8.7 months; localized vs metastatic disease at presentation; P < .001) and elevated lactate dehydrogenase levels were strongly associated with a worse outcome.

CONCLUSION

In comparison to SCLC, less than half of the patients with colorectal HGNEC have history of smoking; metastatic patterns are also different between the 2 cancers. Nevertheless, HGNEC also has an aggressive biology, with the rectum being the most common site of origin. For localized disease, a multimodality approach seems to be associated with better outcomes, while systemic chemotherapy is the mainstay of treatment for advanced disease.

Extrapulmonary small cell carcinoma: imaging features with radiologic-pathologic correlation

Extrapulmonary small cell carcinoma (EPSCC) refers to small cell carcinoma arising outside of the lungs. EPSCC extrapulmonary small cell carcinoma is a rare aggressive neoplasm, representing a minority of all small cell carcinomas. Despite its uncommon occurrence, EPSCC extrapulmonary small cell carcinoma has been described in nearly every organ, most commonly in the gastrointestinal and genitourinary systems. As such, it is important for radiologists to be aware of the entity. Although imaging is neither sensitive nor specific for EPSCC extrapulmonary small cell carcinoma , it plays an important role by helping exclude metastases from a primary pulmonary tumor, establish tumor staging, and assess response to therapy. EPSCC extrapulmonary small cell carcinoma is diagnosed by demonstrating pathologic features of small cell carcinoma in an extrapulmonary site. There are two ways to stage EPSCC extrapulmonary small cell carcinoma . One method uses the Veterans Administration Lung Study Group system developed for small cell lung cancer that allocates patients into limited or extensive disease categories. The second approach is the American Joint Committee on Cancer tumor-node-metastasis system applied to other tumor subtypes arising from the same organ. Because of its rare and varied manifestations, the most effective treatment for EPSCC extrapulmonary small cell carcinoma has not been established. Current management recommendations are derived from retrospective studies and single-institution experiences or are extrapolated from small cell lung cancer data. Regardless of therapy, overall survival rates are poor, with 5-year survival rates around 13%. To help radiologists increase their familiarity with EPSCC extrapulmonary small cell carcinoma , this article provides (a) a background for EPSCC extrapulmonary small cell carcinoma based on the literature and (b) a pictorial review of EPSCC extrapulmonary small cell carcinoma in multiple organs, with radiologic-pathologic correlation.

Metastatic extrapulmonary small cell carcinoma to the cerebellopontine angle: a case report and review of the literature

Extrapulmonary small cell carcinomas (EPSCC) are rare malignancies with poor patient prognoses. We present the case of a 63-year-old male who underwent surgical resection of a poorly differentiated small cell carcinoma, likely from a small intestinal primary tumor that metastasized to the cerebellopontine angle (CPA). A 63-year-old male presented with mild left facial paralysis, hearing loss, and balance instability. MRI revealed a 15 mm mass in the left CPA involving the internal auditory canal consistent with a vestibular schwannoma. Preoperative MRI eight weeks later demonstrated marked enlargement to 35 mm. The patient underwent a suboccipital craniectomy and the mass was grossly different visually and in consistency from a standard vestibular schwannoma. The final pathology revealed a poorly differentiated small cell carcinoma. Postoperative PET scan identified avid uptake in the small intestine suggestive of either a small intestinal primary tumor or additional metastatic disease. The patient underwent whole brain radiation therapy and chemotherapy and at last follow-up demonstrated improvement in his symptoms. Surgical resection and radiotherapy are potential treatment options to improve survival in patients diagnosed with NET brain metastases. We present the first documented case of skull base metastasis of a poorly differentiated small cell carcinoma involving the CPA.