4. Discussion
This report is one of the few in Peru7 and agrees with the clinical presentation reported by Han et al.,4 who have reported that the most common cause of Doege-Potter syndrome is a benign solitary fibrous tumor involving the Right hemothorax associated with pleural damage. Han et al., reported 71 cases of Doege-Potter syndrome, 43 of which (60.6%) were malignant, including SFT of the pelvis, bladder, and retroperitoneum associated with high-frequency hypoglycemia.4
The SFT associated with Doege-Potter syndrome reported in this 74-year-old patient has demonstrated positivity for BCL2 +, focal CD34 +, and Focal CD99 +. Mohammed et al.,5 have reported a large number of lesions that are positive for CD34 + and CD99 +, as well as other case reports, have shown immunoreactivity of these cellular markers.6,7 However, the authors emphasize that these immunohistochemical markers do not have high specificity and may be present in many soft tissue neoplasms.
In this study, we reported negative for actin, S100 protein (S100), and epithelial membrane antigen (EMA), which is different from previous reports that showed positive for smooth muscle actin, EMA, S100, and keratin. Given this particular performance of these markers, STAT6 has turned out to be more specific, being positive in> 95% of the cases, recently reported as part of the pool of tests to address these cases.8
This clinical case has reported Doege-Potter syndrome secondary to the SFT tumor. Although the main paraneoplastic symptom of SFT is osteoarthropathy, hypoglycemia is less than 5%, which is a rare complication. Hypoglycemia is usually secondary to the tumor overproducing IGF II precursor that leads to tumor growth, malignant transformation, and carcinogenesis.9 Our patient had an IGF II concentration of 721 U/I that exceeds the threshold of 10 U/I, indicating an excess production of IGF II characteristic of non-islet cell tumors.4,9,10
Insulin is a 51-amino acid protein with hormone functions, and has mediators such as peptide C in its production process. This hormone is responsible for glycemic control, and in Doege-Potter syndrome it is common for insulin levels to be decreased. As in previous studies,5,6 our patient had low levels of basal insulin (0.04 U / I) and C-peptide (0.01 ng / dL).
It has been described that the most frequent age of SFT is older adults. Several studies have reported SFT in patients aged 67 and 83 years,5,9,11 although there are case series in patients aged 48 years,12 52 years,855 years,6 and 58 years.3 In this study, an elderly patient (74 years old) with Doege-Potter syndrome secondary to benign SFT was reported for the first time in Peru, which is different from previous reports.6
The definitive underlying treatment for Doege-Potter syndrome secondary to benign SFT is palliative debulking, complete resection of the tumor mass, chemotherapy, cryoablation, radiofrequency ablation, or chemoembolization. Previous studies have described complete resection as an effective treatment for this disease, as seen in some cases, including the one we reported in this article.4,5,9 In addition, other surgical techniques with a favourable prognosis have been reported as successful.3,13
With the discovery of the NAB2-STAT6 gene fusion as the characteristic molecular driver of SFT, it is possible that embolization therapy and radiation will be effective. Based on this, individualized therapies aimed at inhibiting the descending pathways of NAB2-STAT6 could be considered for the treatment of this rare group of neoplasms.5
Finally, there is a growing interest in SFT and Doege-Potter syndrome. In Latin America, several cases have been reported in the Argentine,14,15 Peruvian,6Chilean,16 Brazilian,8Colombian,7,11,17,18 and Bolivian19population, showing that even being a rare cause of the paraneoplastic syndrome is of great interest in clinical practice.