Spindle cell XXXX (WHO Type A) with prominent papillary and pseudopapillary features: a clinicopathologic and immunohistochemical study of 10 cases.

@entity1 @entity662 @entity704 @entity1353 @entity5 @entity4 @entity2279 @entity10580 @entity6830 @entity1907
Ten cases of spindle cell @entity704 with prominent papillary and pseudopapillary features were presented. The @entity1 were 7 @entity1 and 3 @entity1 between the ages of 47 and 75 years. Clinically, 3 @entity1 were asymptomatic, 1 @entity1 presented with @entity662 , 4 @entity1 with @entity1353 , and 1 @entity1 with a history of @entity1907 . One case was found during an autopsy procedure. Nine @entity1 underwent complete surgical resection of their mediastinal @entity5 , which varied in size from 4 to 9 cm in greatest diameter. Histologically, all @entity5 showed a spindle cell appearance (WHO type A) with elongated nuclei and inconspicuous nucleoli. Scattered lymphocytes were present admixed with the spindle cellular proliferation. In addition, all @entity5 showed prominent areas of papillary and pseudopapillary features, which varied in size and type. In some cases, prominent areas of hyalinization were also present, whereas in other cases the papillary-like changes were composed of @entity4 projections, which imparted these @entity5 a unique morphologic growth pattern. Three @entity5 were encapsulated, whereas 7 other @entity5 were invasive. Immunohistochemical studies for keratin CAM5.2 and keratin 5/6 showed strong positive reaction, whereas other stains including @entity10580 , calretinin, @entity2279 , and thyroglobulin were negative. Follow-up information showed that 2 @entity1 are alive and well, whereas 3 @entity1 have died. No follow-up information was obtained in 4 @entity1 . The current morphologic appearance has not been previously emphasized in @entity704 , which is important to recognize to avoid misdiagnosis with other @entity6830 .
