Sequential pathological changes during malignant transformation of a craniopharyngioma: A case report and review of the literature

The CD44s Isoform is a Potential Biomarker for Predicting Craniopharyngioma Recurrence in Children

Adamantinomatous craniopharyngioma (ACP) is an intracranial tumor considered partly malignant due to its ability to infiltrate surrounding structures and tendency to relapse despite radical resection. CD44 is a known stem cell marker in ACP and is upregulated in cell clusters of invasive ACP protrusions; however, the functions of its alternative splicing isoform variants, CD44s and CD44v1-10, have not yet been studied in terms of ACP recurrence, despite their confirmed roles in cancer development and progression. In this study, we first confirmed the difference in total CD44 expression between samples from patients who experienced relapse and those from patients who did not. Moreover, our findings showed that, in recurrent samples, the predominant isoform expressed was CD44s, which might indicate its significance in predicting ACP recurrence. The association between increased CD44 expression and recurrence may lead to the development of prognostic markers of ACP aggressiveness and relapse potential; however, further studies are needed to clarify the exact mechanism of CD44 expression.

The effect of radiation therapy and chemotherapy on malignant craniopharyngioma: A review

Background

Malignant craniopharyngioma is a rare tumor with few published case reports. It can form de novo or transform from a benign variant and is associated with a dismal survival rate. We reviewed the literature for all published cases and studied the effect of radiation on the rate of malignant transformation. We analyzed the effect of chemotherapy on survival.

Methods

We used various search engines to locate literature from 1980 onward and identified 31 case reports, one of which was excluded. Statistical analysis using the SAS software was conducted, and a significant value was identified if P < 0.05.

Results

There was equal distribution among male and female patients. The average age at malignant diagnosis is 31.11 years (±15.16) and 12.19 years (±8.41) for the average interval of benign tumor progression to malignancy. The most common clinical presentation was visual loss and/or field deficits in 26/30 patients (86%). Almost 11/30 patients (37%) had endocrinological deficits, with panhypopituitarism as the most common in 8/11 patients (73%). Fifteen patients received radiation before malignant transformation (47%) and demonstrated no effect on malignant transformation (P = 0.379). Gross total resection was achieved in 2/30 patients. The average time to mortality postoperatively is 5.3 months ± 4.3. Ten patients received chemotherapy, and five were alive at last follow-up (P = 0.115).

Conclusion

Malignant craniopharyngioma carries a dismal prognosis with no apparent benefits of radiation therapy and chemotherapy on survival.

Molecular defects in BRAF wild-type ameloblastomas and craniopharyngiomas-differences in mutation profiles in epithelial-derived oropharyngeal neoplasms

The aim of this study was to evaluate the mutation profile of BRAF wild-type craniopharyngiomas and ameloblastomas. Pre-screening by immunohistochemistry and pyrosequencing for identifying BRAF wild-type tumors was performed on archived specimens of ameloblastic tumors (n = 20) and craniopharyngiomas (n = 62). Subsequently, 19 BRAF wild-type tumors (nine ameloblastic tumors and ten craniopharyngiomas) were analyzed further using next-generation sequencing (NGS) targeting hot spot mutations of 22 cancer-related genes. Thereby, we found craniopharyngiomas mainly CTNNB1 mutated (8/10), including two FGFR3/CTNNB1-double mutated tumors. Ameloblastic tumors were often FGFR2 mutated (4/9; including one FGFR2/TP53/PTEN-triple mutated case) and rarely CTNNB1/TP53-double mutated (1/9) and KRAS-mutated (1/9). In the remaining samples, no mutation could be detected in the 22 genes under investigation. In conclusion, mutation profiles of BRAF wild-type craniopharyngiomas and ameloblastomas share mutations of FGFR genes and have additional mutations with potential for targeted therapy.

Pathologic aspects of skull base tumors

Skull base tumors form a highly heterogeneous group. As there are several structures in this anatomical site, a large number of different primary malignancies might develop, as well as a variety of secondary (metastatic) tumors. In this article, the most common malignancies are presented, along with a short histopathologic description. For some entities, an immunohistochemical profile is also given that should be helpful in proper diagnosis. As many pathologic diagnoses nowadays also include genetic studies, the most common genetic abnormalities in skull base tumors are presented.

Concise Review: Paracrine Role of Stem Cells in Pituitary Tumors: A Focus on Adamantinomatous Craniopharyngioma

The existence of tissue‐specific progenitor/stem cells in the adult pituitary gland of the mouse has been demonstrated recently using genetic tracing experiments. These cells have the capacity to differentiate into all of the different cell lineages of the anterior pituitary and self‐propagate in vitro and can therefore contribute to normal homeostasis of the gland. In addition, they play a critical role in tumor formation, specifically in the etiology of human adamantinomatous craniopharyngioma, a clinically relevant tumor that is associated with mutations in CTNNB1 (gene encoding β‐catenin). Mouse studies have shown that only pituitary embryonic precursors or adult stem cells are able to generate tumors when targeted with oncogenic β‐catenin, suggesting that the cell context is critical for mutant β‐catenin to exert its oncogenic effect. Surprisingly, the bulk of the tumor cells are not derived from the mutant progenitor/stem cells, suggesting that tumors are induced in a paracrine manner. Therefore, the cell sustaining the mutation in β‐catenin and the cell‐of‐origin of the tumors are different. In this review, we will discuss the in vitro and in vivo evidence demonstrating the presence of stem cells in the adult pituitary and analyze the evidence showing a potential role of these stem cells in pituitary tumors. Stem Cells2016;34:268–276