# Atypical Cystic Primary Hepatic GIST: A Case Report of Rare Presentation and Long-Term Survival

## TL;DR

A rare case of a mostly cystic liver tumor in a 79-year-old woman showed long-term survival through personalized treatment, challenging current understanding of these tumors.

## Contribution

This case report presents a rare cystic presentation of PHGIST with an unusually long survival period due to individualized treatment strategies.

## Key findings

- The patient survived 8 years with a cystic PHGIST through multiple surgeries and targeted therapies.
- The tumor showed atypical resistance patterns to imatinib and sunitinib, highlighting the need for personalized treatment.
- Surgical intervention in advanced stages significantly contributed to prolonged survival.

## Abstract

Primary hepatic gastrointestinal stromal tumours (PHGISTs) are rare and often misdiagnosed because of their unusual liver location. Typically, these tumours are solid and have a poor prognosis. This article presents a unique case of a 79-year-old woman with a mostly cystic PHGIST who survived for eight years, challenging the usual understanding of these tumours. Her long survival was due to personalized treatment, including multiple surgeries and targeted therapies, showing that individualized care leads to better outcomes. These findings suggest that PHGISTs can appear in unexpected forms, indicating the need for a team approach and continuous monitoring. Additionally, the patient developed resistance to initial treatments, emphasizing the importance of ongoing research into genetic and molecular characteristics to develop more effective therapies. Future research should focus on developing advanced imaging techniques and genetic testing to improve early detection and treatment. Integrating personalized treatment plans and multidisciplinary care could significantly enhance patient outcomes.

Primary hepatic gastrointestinal stromal tumours (PHGISTs) are rare and frequently misdiagnosed due to their atypical presentation and uncertain origin. The purpose of this article is to present the case of a 79-year-old female patient with a gigantic PHGIST characterized by a predominantly cystic nature—an extremely rare presentation, as most cases of PHGIST are solid. Despite extensive imaging and exploratory laparotomy, the primary origin remained uncertain, leading to questioning about whether it was a true primary hepatic GIST or an atypical metastatic lesion. The initial therapeutic approach involved a surgical procedure aimed to confirm the diagnosis and achieve reductive tumourectomy. Following the surgery, the patient was administered imatinib with a favourable clinical response for four and a half years—an atypical pattern of resistance, as most patients typically develop therapeutic resistance within two to three years. A second surgical intervention was performed to address a cystic lesion localized in the left hepatic lobe, followed by an atypical segment III hepatectomy to achieve macroscopic resection. Subsequently, the patient received sunitinib for two and a half years, which resulted in temporary disease stabilization. However, the sunitinib treatment was associated with hypertension and leukopenia. The patient’s overall survival was 8 years, suggesting that individualized therapeutic strategies and close monitoring might be the key in such cases. Furthermore, this case confirms the role of surgical intervention even in advanced disease stages, with multiple major resections contributing significantly to prolonged survival. The interplay between surgical and oncologic therapies remains essential to guiding clinical decisions. Given the unusual cystic presentation, this case highlights the necessity to expand the pathological and molecular profiling of PHGISTs. Furthermore, the atypical timeline of resistance development and treatment-related toxicity emphasizes the importance of further research into the genetic and pharmacological determinants of PHGISTs. These findings advocate for the refinement of diagnostic, therapeutic, and surveillance protocols tailored to rare GIST subtypes.