Extrapancreatic solid pseudopapillary neoplasm: Report of a case of primary retroperitoneal origin and review of the literature

Abstract

Solid pseudopapillary tumors (SPTs) occurring as primary tumors outside the pancreas are exceedingly rare. The present study reports such a case occurring as a non-functional adrenal tumor in a 22-year-old female. The tumor was completely removed from the retroperitoneum by laparoscopic surgery. A well-defined, encapsulated tumor measuring 6×6×5 cm was histologically characterized by a combination of the solid and pseudopapillary growth patterns of tumor cells with eosinophilic cytoplasm. Ectopic pancreatic tissue was also found histologically within the resected tumor. On immunostaining, the tumor was positive for progesterone receptor, CD56, cytokeratin and CD10. The morphological and immunohistochemical features were compatible with those of SPT. To the best of our knowledge, this is the first case report of extrapancreatic SPT with evidence of a pre-existing ectopic pancreas in the retroperitoneum. A review of the published English literature uncovered 12 cases of extrapancreatic SPTs, and revealed that extrapancreatic SPTs are likely to have a favorable clinical course and a clinical profile similar to their pancreatic counterparts.

Solid pseudopapillary neoplasm of the pancreas in children: Hacettepe experience

“…In our series, the head of the pancreas was the most common location followed by the body and tail. Very rarely, SPNP has been described outside the pancreas . In one of our cases (#3), the tumour was located outside the pancreas near the left liver lobe and was resected totally.…”

Solid-pseudopapillary Neoplasms of the Pancreas is still an Enigma: a Clinicopathological Review

“…2f). Presence of progesterone receptor is regularly detected [8,12,31,48,50] (Fig. 2g), androgen receptor is expressed in about 80% of cases [43], but the estrogen receptor is usually negative [48,50,53].…”

“…Regarding the localization, there is no preference of it; any part of the pancreas can be the site of origin. Although it is a primary pancreatic neoplasm, exceedingly rarely it may also occur in extrapancreatic places (omentum, adrenal or mesentery) [11][12][13]. As a rule, the neoplasm presents as a solitary lesion, the multicentric manifestation is a curiosity [14].…”

Limited usefulness of histopathological features in identification of a clinically aggressive solid-pseudopapillary neoplasm of the pancreas

“…It develops almost exclusively in the pancreas, with the exception of extremely rare cases present in other areas/organs of the abdominal cavity [40,41,85,86]. The origin of SPN is still unknown [4], but its relation to stem cells of the pancreas [87], centroacinar cells [80,88], genital ridge-related cells [78] or neural crest [89] was postulated.…”

“…The clinical factors included: male gender [5,18,32], patient's age [5,18,[32][33][34], body mass index [18], serum tumour markers [18,33], presence of symptoms [18,32], mean duration of symptoms [18,32], non-resectability [35], extent of surgery [5,36], familial occurrence of tumour [37], and multiple primary lesions in a single patient [38,39]. Histopathological factors included: extrapancreatic localization of the main neoplastic mass [40,41], localization of tumour within particular segment of the pancreas [5,18,32], tumour diameter [5,32,42], gross characteristics of tumour (solid, cystic, or mixed) [18,32,43], tumour rupture [43][44][45], lack of a tumour capsule [46] and incomplete capsule [47], capsule invasion [17,18,33,48], invasion into pancreatic parenchyma [17,33,49] or adjacent tissues or organs (invasion of duodenum, spleen, common bile duct, peripancreatic fat) …”