Pheochromocytoma and paraganglioma characteristically form small nests of uniform polygonal chromaffin cells ("zellballen"). A diagnosis of malignancy can only be made by identifying tumor deposits in tissues that do not normally contain chromaffin cells (e.g., lymph nodes, liver, bone, lung, and other distant metastatic sites).
Regional or distant metastatic disease is documented on initial pathology in only 3% to 8% of patients; thus, an attempt has been made...
Liposarcoma is rare in the pediatric population. In a review of 182 pediatric patients with adult-type sarcomas, only 14 had a diagnosis of liposarcoma. One retrospective study identified 34 patients younger than 22 years from 1960 to 2011. There were roughly equal numbers of male and female patients and the median age was 18 years. In an international clinicopathological review, the characteristics of 82 cases of pediatric liposarcoma were reported. The median age was 15.5 years and females were more commonly affected. In both reports, the great majority of patients had myxoid liposarcoma.
Liposarcomas can be roughly divided into the following four large groups:
Atypical lipomatous neoplasm/well-differentiated liposarcoma. These tumors do not metastasize unless they undergo dedifferentiation.
Myxoid liposarcoma. Pure myxoid liposarcomas are characterized by a t(12;16)(q13;p11) translocation and can metastasize but usually have an excellent outcome in the absence of a round cell component.
The great majority of liposarcomas in the pediatric and adolescent age range are low grade. Myxoid liposarcoma is typically low grade. Pleomorphic liposarcoma is typically high grade and much more likely to develop metastasis. Metastasis to lymph nodes is very uncommon, and the great majority of metastases are pulmonary. Tumors arising in the periphery are more likely to be low grade and myxoid. Tumors arising centrally are more likely to be high grade, pleomorphic, and present with metastasis or recur with metastasis.
Surgery is the most important treatment for liposarcoma. After surgical resection of myxoid liposarcoma, event-free survival (EFS) and overall survival (OS) are roughly 90%. Local recurrences have been seen and are controlled with a second resection of the tumor. Higher grade or central tumors are associated with a significantly higher risk of death. In a retrospective review, 5-year survival for central tumors was 42%. In the international review, seven of ten patients with pleomorphic myxoid liposarcoma died because of their disease. If initial surgery is incomplete, re-excision should be performed to achieve a wide margin of resection. There are reports of the use of chemotherapy to decrease the size of liposarcoma prior to surgery to facilitate complete resection, particularly in central tumors.[4,5] The role of adjuvant chemotherapy for liposarcoma is poorly defined. There does not appear to be a need for any adjuvant therapy for completely resected myxoid liposarcoma. Even with the use of adjuvant chemotherapy, the survival of pleomorphic liposarcoma remains poor.