Does mesoappendix infiltration predict a worse prognosis in incidental neuroendocrine tumors of the appendix? A clinicopathologic and immunohistochemical study of 15 cases.
We conducted a retrospective clinicopathologic and immunohistochemical study of the biologic significance of mesoappendix infiltration in 15 appendiceal neuroendocrine tumors selected from a series of 42 primary tumors. In all cases, the tumor was found incidentally and measured less than 2 cm (mean, 0.84 cm). In 13 cases, it was located in the tip of the appendix and in the midportion in 2. Histologically, none showed relationship with overlying mucosa. Necrosis was absent; mitotic figures were rare. The Ki-67 labeling index was low (1%-2%). In all cases, S-100 protein immunostaining disclosed positive elements with cytoplasmic dendritic processes closely intermingled with neuroendocrine neoplastic cells. All patients (8 males; 7 females; mean age, 38.2 years) underwent simple appendectomy. A right-sided hemicolectomy was performed subsequently in 1 case. After a mean follow-up of 52.6 months (range, 8-143 months), none had died of disease or had recurrent or metastatic disease. Our results confirm that appendiceal neuroendocrine tumors seem to have a different phenotype from those occurring in other gastrointestinal sites. Tumors less than 2 cm, even with mesoappendiceal infiltration, have an excellent prognosis, and simple appendectomy seems to be the appropriate therapeutic approach.
Rossi
Giulio
G
Department of Pathologic Anatomy and Forensic Medicine, Section of Pathology, University of Modena and Reggio Emilia, via del Pozzo, 71, 41100-Modena, Italy.
Valli
Riccardo
R
Bertolini
Federica
F
Sighinolfi
Pamela
P
Losi
Luisa
L
Cavazza
Alberto
A
Rivasi
Francesco
F
Luppi
Gabriele
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001063:Appendiceal Neoplasms / Q000737:chemistry / Q000473:pathology*; D001065:Appendix / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000737:chemistry / Q000473:pathology*; D011379:Prognosis; D009418:S100 Proteins / Q000032:analysis
D009418:S100 Proteins; D007633:Keratins