Primary papillary epithelial tumour of the sella: expanding the spectrum of TTF-1-positive sellar lesions

Pituitary spindle cell oncocytoma: Two cases report and literature review

INTRODUCTION

Pituitary spindle cell oncocytoma (PSCO) is a seldom-encountered type of pituitary neoplasm with distinctive histological features. It was first described as a distinct entity by Roncaroli et al. in 2002. We present two cases of PSCO and discuss its clinical, radiological, and histopathological features, along with a review of the existing literature.

PRESENTATION OF CASE

Two cases underwent trans-nasal transsphenoidal surgery for tumor resection and had different treatment following would be discussed in this article. Both had unique pathology pattern as Pituitary spindle cell oncocytoma.

DISCUSSION

Tumors positive for TTF-1 in the sellar region, such as pituicytoma, granular cell tumor, and spindle cell oncocytoma, originate from the posterior pituitary gland and are rare. The expression of thyroid transcription factor-1 (TTF-1) in these tumors aids in distinguishing them from other pituitary neoplasms.

CONCLUSION

Pituitary spindle cell oncocytoma is a rare entity among pituitary tumors. This case report highlights the clinical, radiological, histopathological, and immunohistochemical features of PSCO. Surgeons and pathologists should consider this rare diagnosis in patients with sellar and suprasellar masses, as early recognition and complete surgical resection can lead to favorable outcomes.

Primary papillary epithelial tumor of the sella: a case report of an emerging tumor type

Primary papillary epithelial tumor of the sella (PPETS) is a newly described tumor entity with prototypical location in the sella. Only two case series with ten cases have been described so far. These tumours have a typical papillary architecture with bland nuclear features, TTF-1 immunopositivity and low MIB-1-labelling index. Many of these tumours were previously assigned under the category of 'ectopic choroid plexus papilloma'. PPETS expands the group of TTF-1 positive tumours of the central nervous system. Histomorphology plays an essential role in making this diagnosis. We report a case of 44-year-old female with a sellar mass lesion, who presented with progressive loss of vision and diagnosed as primary papillary epithelial tumor.

Spindle cell oncocytoma of the pituitary tumor: A rare case report and literature reviews

Introduction

Spindle cell oncocytoma (SCO) of the pituitary gland is increasingly established with improvements in histological and immunohistochemical examination. However, the diagnosis was often mistaken based on imaging studies and nonspecific clinical manifestations.

Purpose

This case is presented to provide an overview of the characteristics of the rare tumor as well as to demonstrate the difficulties in diagnosis and current treatments.

Clinical discussion

The pathogenesis of SCO remains unclear, and a possible origin was described. Further research is needed to optimize pre-operative diagnosis and surgical strategy.

Conclusion

SCO should be considered when images indicate some features. Gross total resection (GTR) after surgery seems to have better long-term tumor control, and radiotherapy may help decrease tumor progression in patients with non-GTR. Regular follow-up is advised because of the higher recurrence rate.

Dabrafenib monotherapy for a recurrent BRAFV600E-mutated TTF-1-positive posterior pituitary tumor

Posterior pituitary tumors (PPT) expressing thyroid transcription factor-1 (TTF-1) are extremely rare low-grade neoplasms. The recent discovery of BRAF mutations in these tumors offers a potential alternative treatment using targeted therapies. We present the case of a 57-year-old female with recurrent BRAFV600E-mutated TTF-1-positive PPT treated with a BRAF inhibitor monotherapy (dabrafenib) leading to tumor regression. After 18 months of uninterrupted treatment, ongoing radiological tumor regression was observed and the patient remained asymptomatic without any significant adverse event. BRAF inhibitor is potentially a valuable treatment option for recurrent TTF-1-positive PPT with BRAF mutation.

Posterior pituitary tumours: patient outcomes and determinants of disease recurrence or persistence

OBJECTIVE

Posterior pituitary tumours (PPTs) are rare neoplasms with the four recognised subtypes unified by thyroid transcription factor -1 (TTF-1) expression, according to the 2017 WHO classification. Though traditionally defined as low-grade neoplasms, a substantial proportion of them show recurrence/persistence following surgery.

METHODS

We selected patients with PPTs in our cohort of 1760 patients operated for pituitary tumours over the past 10 years (2010-2019). The clinical, radiological, hormonal, histopathological profiles and long-term outcomes of the three cases identified (two pituicytomas and one spindle cell oncocytoma, SCO) were analysed. Following a literature review, data of all published cases with documented TTF-1 positive pituicytomas and SCOs were analysed to determine the predictors of recurrence/persistence in these tumours.

RESULTS

Patients presented with compressive features or hypogonadism. Two had sellar-suprasellar masses. One had a purely suprasellar mass with a pre-operative radiological suspicion of pituicytoma. Two were operated by transsphenoidal surgery and one transcranially guided by neuronavigation. Histopathology confirmed spindle cells in a storiform arrangement and low Ki67 index. Immunohistochemistry showed positive TTF-1, S-100 expression and variable positivity for EMA, vimentin and GFAP. Re-evaluation showed recurrence/persistence in two patients. A literature review of recurrent/persistent pituicytoma (n = 17) and SCO (n = 9) cases revealed clinical clues (headache for pituicytomas, male gender for SCO), baseline tumour size (≥20.5 mm with sensitivity exceeding 80%) and longer follow-up duration as determinants of recurrence/persistence.

CONCLUSION

PPTs are rare sellar masses with quintessential TTF-1 positivity. Recurrent/persistent disease following surgery is determined by greater tumour size at baseline and duration of follow-up. This warrants intensive and long-term surveillance in these patients.

A Comprehensive Study of Spindle Cell Oncocytoma of the Pituitary Gland: Series of 6 Cases and Meta-Analysis of 85 Cases

OBJECTIVE

To discuss optimal treatment strategy for spindle cell oncocytoma (SCO) of the pituitary gland.

METHODS

Institutional cases were retrospectively reviewed. A systematic literature search and subsequent quantitative synthesis were performed for further analysis. The detailed features were summarized and the tumor control rate (TCR) was calculated.

RESULTS

Eighty-five patients (6 institutional and 79 literature) were included. The annual incidence was approximately 0.01-0.03/100,000. The mean age was 56 years. Vision loss was present in 60%. Seventy-three percent showed hormonal abnormalities. On magnetic resonance imaging, tumor was avidly enhancing, and the normal gland was commonly displaced anterosuperiorly. Evidence of hypervascularity was seen in 77%. Gross total resection (GTR) was achieved in only 24% because of its hypervascular, fibrous, and adhesive nature. The mean postoperative follow-up was 3.3 years for institutional cases and 2.3 years for the integrated cohort. The TCR was significantly better after GTR (5-year TCR, 75%; P = 0.012) and marginally better after non-GTR + upfront radiotherapy (5-year TCR, 76%; P = 0.103) than after non-GTR alone (5-year TCR, 24%). The TCRs for those with low Ki-67 index (≤5%) were marginally better than those with higher Ki-67 index (5-year rate, 57% vs. 23%; P = 0.110).

CONCLUSIONS

Frequent endocrine-related symptoms, hypervascular signs, and anterosuperior displacement of the gland support preoperative diagnosis of SCO. GTR seems to have better long-term tumor control, whereas the fibrous, hypervascular, and adhesive nature of SCO makes it difficult to achieve GTR. In patients with non-GTR, radiotherapy may help decrease tumor progression.