Kevin O'Regan

Positron emission tomography/computed tomography imaging in Merkel cell carcinoma: A study of 270 scans in 97 patients at the Dana-Farber/Brigham and Women's Cancer Center

BACKGROUND Merkel cell carcinoma (MCC) is a rare and lethal cutaneous neuroendocrine carcinoma. Imaging is crucial for accurate staging, which remains a strong predictor of survival, as well as earlier detection of recurrence and progression, which are common despite aggressive management. There is no consensus on the role of initial and subsequent imaging for MCC. OBJECTIVE We sought to evaluate the use of 2-fluoro-[(18)F]-deoxy-2-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in the management of MCC. METHODS In all, 270 FDG-PET/CT studies were performed in 97 patients with pathology-proven MCC at the Dana-Farber/Brigham and Womens Cancer Center, Boston, Mass, from August 2003 to December 2010. RESULTS FDG-PET/CT scans were obtained as part of the initial (61 scans in 61 patients) and subsequent (209 scans in 79 patients) treatment strategies. MCCs were FDG-avid with a mean maximum standardized uptake value of primary lesions of 6.5 (range 1.3-12.9) and a mean maximum standardized uptake value of regional and distant metastases of 7.2 (range 1.5-9.9). FDG-PET/CT upstaged 16% of patients who underwent baseline scans. FDG-PET/CT studies showed that bone and bone-marrow metastases were more common than previously reported, and were often undetected by CT. LIMITATIONS Our study is limited by its retrospective design, and potential referral bias associated with a tertiary care center. CONCLUSIONS FDG-PET/CT performed as part of the initial management strategy tended to upstage patients with more advanced disease. FDG-PET/CT performed as part of the subsequent treatment strategy identified metastatic disease, particularly in bone/bone marrow, which was not seen on CT. FDG-PET/CT imaging is a valuable staging and restaging tool in MCC management.

Radiologic Aspects of Immune-Related Tumor Response Criteria and Patterns of Immune-Related Adverse Events in Patients Undergoing Ipilimumab Therapy

OBJECTIVE The objective of this article is to illustrate examples of radiologic immune-related response criteria and toxicity in patients with advanced melanoma treated with the immunotherapeutic agent ipilimumab. CONCLUSION Novel immune-related tumor response criteria should be applied to patients undergoing therapy with ipilimumab for advanced melanoma. Ipilimumab also produces a spectrum of immune-related adverse effects that can be recognized radiologically.

Spleen in haematological malignancies: spectrum of imaging findings

Imaging morphology and metabolic activity of splenic lesions is of paramount importance in patients with haematological malignancies; it can alter tumour staging, treatment protocols and overall prognosis. CT, MRI and positron emission tomography (PET)/CT have been shown to be powerful tools for the non-invasive assessment of splenic involvement in various haematological malignancies. Since many haematological malignancies and non-neoplastic conditions can involve the spleen and imaging manifestations can overlap, imaging and clinical findings outside of the spleen should be looked for to narrow the differential diagnosis; confirmation can be obtained by pathological findings. Radiologists should be familiar with the cross-sectional imaging patterns of haematological malignancies involving the spleen as well as non-neoplastic splenic findings common in these patients to facilitate their care and follow-up. This pictorial review provides the common and uncommon imaging appearances and complications of various haematological malignancies involving the spleen on CT, MRI and PET/CT, and common pitfalls in diagnosis.

Imaging of liposarcoma: classification, patterns of tumor recurrence, and response to treatment.

OBJECTIVE The purpose of this study was to illustrate the subtypes of liposarcoma (LPS) and the significance of the nonlipomatous tumor components using multiple imaging modalities. CONCLUSION The subtypes of LPS with greater nonlipomatous soft-tissue components on imaging studies tend to show less differentiation and are usually more aggressive both histologically and clinically. Imaging plays an important role in the diagnosis, surveillance, and response assessment of LPS.

Extraskeletal Osteosarcoma: Spectrum of Imaging Findings

OBJECTIVE The purpose of this article is to present the spectrum of imaging findings of primary and metastatic extraskeletal osteosarcoma and highlight the differences from primary osteogenic osteosarcoma in bone. CONCLUSION Extraskeletal osteosarcoma is a rare mesenchymal malignancy of soft tissue, histologically indistinguishable from primary osteosarcoma of bone. However, there are distinct differences in demographics, imaging features, prognosis, and management compared with osteogenic osteosarcoma. Imaging characteristics reflect tumor morphology, with only 50% of primary tumors showing mineralization. Metastases may or may not show mineralization, even if present in the primary tumor. The overall prognosis is poor.

Imaging features of bowel toxicities in the setting of molecular targeted therapies in cancer patients

Molecular targeted therapies are becoming ubiquitous in cancer treatment. These drugs may cause gastrointestinal toxicities including perforation, pneumatosis, enteritis, colitis and fistula formation. Knowledge of these complications and their management enables early radiological identification and appropriate intervention, reducing patient morbidity and mortality.

Imaging features of primary and secondary malignant tumours of the sacrum

Malignant tumours of the sacrum may be primary or secondary. While sacral metastases are frequently encountered, a diagnostic dilemma can present when there is a single sacral bone tumour with no history or evidence of malignancy elsewhere in the body. Familiarity with the imaging features and clinical presentations of primary malignant bone tumours is helpful in narrowing the differential. This pictorial review will illustrate with both common and uncommon malignant sacral tumours CT, MRI and positron emission tomography/CT, highlighting the specific features of each.

Imaging of desmoplastic small round cell tumour in adults

Desmoplastic small round cell tumour (DSRCT) belongs to the histological descriptive category of small round blue cell tumours. DSRCT primarily occurs in adolescents and young adults between the ages of 15 and 25 years and has a male predominance. DSRCT is an aggressive disease with a poor prognosis; timely diagnosis is therefore critical to the management of these patients. Although their radiographic appearances overlap with other aggressive malignancies, there are certain imaging features that can suggest the diagnosis and expedite the initiation of appropriate therapy. The aim of our pictorial review is to describe the imaging findings of primary and metastatic DSRCT in adults.

The role of 18F‐FDG PET/CT imaging in Waldenstrom macroglobulinemia

Disease assessment in WM is dependent on the quantification of the IgM monoclonal protein and percent involvement of the bone marrow. There is a need for imaging studies that objectively measure tumor load in these patients. In this study, we sought to examine the role of combined FDG‐PET/CT imaging in the detection of tumor load and in the assessment of response to therapy. Thirty‐five patients were enrolled on a prospective study using bortezomib and rituximab therapy and were included in this study because they completed a pre‐ and post‐treatment FDG‐PET/CT imaging at one facility (12 newly diagnosed and 23 relapsed/refractory). The use of combined FDG‐PET/CT imaging showed positive findings in 83% of patients with WM, unlike prior studies using conventional imaging that indicate that only 20% of patients have lymphadenopathy or hepatosplenomegaly. Moreover, 43% of patients had abnormal bone marrow uptake on FDG‐PET imaging that can potentially help in the assessment of their tumor load, especially with heterogenous sampling of the bone marrow. There was no statistical correlation between EORTC response criteria for FDG‐PET/CT and response by monoclonal protein. This is the first study to examine the role of FDG‐PET/CT imaging in WM. Future studies should examine the role of FDG‐PET/CT in conjunction with monoclonal protein response in the assessment of progression‐free survival in patients with WM. Am. J. Hematol., 2011.

Extrapulmonary Small Cell Carcinoma: A Pictorial Review

OBJECTIVE Extrapulmonary small cell carcinoma (EPSCC) is a rare, aggressive neoplasm arising from virtually any organ. Numerous oncologic studies have addressed prognostic indicators and survival rates in EPSCC, however relatively little has been published regarding the imaging features and metastatic patterns of these uncommon tumors. This article provides a pictorial review of EPSCC in multiple organs, emphasizing the imaging appearance at presentation and the radiologic patterns of recurrence/metastasis. CONCLUSION Although the appearance of EPSCC is often nonspecific, the typical presentation is large aggressive tumors that, similar to small cell carcinoma in the lung, often respond well to local therapy but tend to recur relentlessly at distant sites.