Leiomyoblastoma: Behavior and prognosis

Abstract

Four cases of leiomyoblastoma are presented which illustrate the clinical presentations and gross anatomical appearance associated with this type of tumor when it is clinically significant. Case 1 is unique in having a markedly elevated mitotic rate with no evidence of metastasis at autopsy; it is the third case presenting as a pancreatic pseudocyst. Twenty‐two cases of leiomyoblastoma reported in the literature since 1962 are reviewed. Experience with varying clinical presentations, gross anatomical and histologic appearances, and results of surgical therapy are summarized. Seven examples of metastasis of this tumor have been reported. In each case the rate of mitosis had significantly increased. Case 1 of our series had a mitotic rate from 2 to 3 times higher than those that metastasized, but no evidence of metastasis was present at autopsy. There may be variants of leiomyoblastomas with elevated mitotic rates that do not metastasize or do so only after a protracted course. Nevertheless, the mitotic rate remains die best criterion for prognosis.

Gastrointestinal stromal tumours: from KIT to succinate dehydrogenase

“…As recently as the 1990s, GISTs were thought to be smooth muscle neoplasms, and were consequently often diagnosed as leiomyomas, ‘leiomyoblastomas’, or leiomyosarcomas . Other historical designations included GANT (gastrointestinal autonomic nerve tumour), based on particular ultrastructural characteristics found in a subset of tumours .…”

“…The discovery of these mutations has served as an excellent model for the development of effective molecularly targeted thera-often diagnosed as leiomyomas, 'leiomyoblastomas', or leiomyosarcomas. [4][5][6] Other historical designations included GANT (gastrointestinal autonomic nerve tumour), based on particular ultrastructural characteristics found in a subset of tumours. 7,8 It is now well established that, in fact, GISTs show differentiation towards (or arise from) the interstitial cells of Cajal, which reside in the myenteric plexus and between smooth muscle fibres of the muscularis propria, where they function as pacemaker cells for peristalsis.…”

Torsion of a gastric leiomyoma

“…T h e diagnosis of extraluminal gastric leiomyomas is difficult. Schofield and Fox (1965) and Smithwick, Beisecker, and Leand (1969) described separate cases i n which the tumour enlarged into the lesser sac and a diagnosis of pancreatic pseudocyst was made.…”