PANCREATOBLASTOMA - A CLINICOPATHOLOGICAL STUDY AND REVIEW OF THE LITERATURE

Pancreatoblastoma is a rare pancreatic tumor with a distinctive histol ogic appearance that generally affects infants and young children. We have studied 14 cases of pancreatoblastoma and reviewed 41 previously reported examples. Nine of our cases occurred in children (from newbor n to 4 years old; mean, 2.4), and five affected adults (from 19 to 56 years old; mean, 40). There were 8 male cases and 6 female cases. Most patients presented with incidental abdominal masses, although pain, w eight loss, and obstructive jaundice were present, but rarely. The tum ors were very cellular microscopically, with cytologically uniform epi thelial cells arranged in sheets and nests. Well-formed acinar structu res were a consistent feature, and several cases contained ectatic duc tular formations, rarely exhibiting intracellular mucin. Consistently present were squamoid corpuscles: circumscribed, whorled nests of plum p spindle cells with a squamous appearance and occasional keratinizati on. The stroma was moderate to abundant and frequently quite cellular (especially in the pediatric cases). By immunohistochemistry, the tumo rs exhibited acinar, endocrine, and ductal differentiation, with posit ivity for pancreatic enzymes (100%), endocrine markers (82%), and carc inoembryonic antigen (85%). Ultrastructural examination most commonly revealed acinar differentiation, although mucigen granules and neurose cretory granules were also occasionally found. The behavior was variab le: 36% of patients developed metastases, especially to the liver. The adult patients did poorly: three of five died of tumor (mean survival , 18 months), and two were alive at 5 and 15 months, respectively. In contrast, five of the six evaluable pediatric patients were alive from 22 months to 22 years after diagnosis, and only one died of tumor aft er 16 months. Good responses to chemotherapy were noted in the pediatr ic group.