Spindle cell oncocytoma with late recurrence and unique neuroimaging characteristics due to recurrent subclinical intratumoral bleeding

Abstract

Spindle cell oncocytoma (SCO) is a rare sellar-region tumor recently codified in the World Health Organization (WHO) 2007 Classification as a grade I neoplasm. Despite this grading, recurrences have been demonstrated but, to date, extensive recurrent bleeding into these tumors has not been documented. A 70-year-old woman first presented in 1996 with visual difficulties and was found to have a sellar-region mass with heterogeneous neuroimaging features, leading to preoperative diagnosis of craniopharyngioma. Transsphenoidal, gross total resection was achieved despite extensive intraoperative bleeding; pathology showed an unusual spindle cell neoplasm which could not be further classified. She received no further treatment and was lost to our follow-up until 2009, when she again presented with visual deterioration. Neuroimaging demonstrated recurrence of a large sellar-region tumor with heterogeneous signal characteristics, prompting re-resection. Review of her original and recurrent tumor allowed diagnosis of SCO; extensive intratumoral hemorrhage of varying ages and widespread hemosiderin accounted for her complex neuroimaging features. Vimentin, S100, and galectin-3 immunoreactivity was consistent with SCO. EM demonstrated abundant mitochondria, short intercellular junctions, and absence of neurosecretory granules. Thyroid disease was documented clinically. SCOs are sufficiently rare that documentation of unusual features is important. Recurrent bleeding with resultant complex neuroimaging is unique to this case, but appears to overlap with a related sellar-region tumor, pituicytoma. The presence of thyroid disease also links SCO with pituicytoma. The 13-year interval to recurrence is the longest reported to date in SCO; WHO grade I designation may be premature for this neoplasm.

Spindle Cell Oncocytoma of the Adenohypophysis With Marked Hypervascularity

“…In most cases, local control was achieved in the short term, but tumor recurrence was noted in the longer follow-up period (with a maximum interval of 13 years) despite gross total resection (Case 14). 1) Recurrence took place not only in cases with high MIB-1 indices but also in cases with low indices (Case 15). 4) Together, these findings suggest that patients with SCO should be carefully followed up for long periods and that it may be premature to assign this tumor to only WHO grade 1.…”

“…4) Together, these findings suggest that patients with SCO should be carefully followed up for long periods and that it may be premature to assign this tumor to only WHO grade 1. 1) No angiographic description of SCO has been reported. In five cases (Cases 9, 11, 14, 15, and 16), the tumor was judged to be hypervascular based on preoperative MR imaging in one case (Case 14) and intraoperative extensive bleeding in four cases (Cases 9, 11, 15, and 16).…”

“…This tumor shows not only similar morphology to SCO but also hypervascularity, and occasionally induces intraoperative massive bleeding. 1,6) Pituicytoma normally shows immunoreactivity for GFAP and lacks mitochondrial proliferation, so immunohistochemistry and electron microscopy are essential for the distinction. The present case of SCO was initially misdiagnosed as schwannoma.…”

“…MIB-1 index was 3% (D: original magnification ×100). [1][2][3][4]8,9,11,12) The clinical and radiological features of SCO are nonspecific and indistinguishable from those of non-functioning macroadenoma, but its histological profile is quite different; the tumor consists of interwoven fascicles of spindle cells exhibiting abundant eosinophilic cytoplasm, rare mitosis, but no necrosis. The tumor cells show immunoreactivity for vimentin, S-100 protein, and epithelial membrane antigen (EMA), and the cytoplasm contains abundant mitochondria.…”

The New World Health Organization Classification of Central Nervous System Tumors: What Can the Neuroradiologist Really Say?

“…Few tumors with imaging findings have been reported. 31,32 Most reported cases present as intrasellar masses with suprasellar extension. Both clinical and radiologic features are indistinguishable from nonfunctioning pituitary macroadenomas (Fig 11B).…”