Case Presentation A 26-year-old white female from Uberaba presented with a chronic history of mid-abdominal
colicky pain, associated with nausea and excessive flatulence. She was admitted to
the emergency department due to exacerbation of pain for the past 3 days, with abdominal
distension and cessation of stool and gas passage after the onset of symptoms. She
denied fever, chills, anorexia, urinary changes, or previous similar episodes. The
patient was previously healthy, using only oral contraceptives. On physical examination,
she was in good general condition, afebrile, with a tense abdomen, diffusely tender
on palpation, with increased pain in the right iliac fossa, along with guarding and
positive rebound tenderness in this region. A contrast-enhanced abdominal CT scan
was performed, revealing findings consistent with acute appendicitis and diffuse thickening
of the cecal appendix. The patient underwent laparoscopic appendectomy without complications,
and the pathological analysis of the specimen revealed significant thickening of the
appendix wall at the base. The histopathological study showed an epithelioid neoplasm
with expansive growth and perivascular involvement, with cells having ample cytoplasm,
sometimes clear, sometimes eosinophilic granular, with a tendency to merge with the
adjacent muscle layer and without nuclear atypia. The immunohistochemical analysis
was positive for smooth muscle actin and GP100 protein, and negative for other antibodies,
confirming the diagnosis of PEComa of the cecal appendix. Thoracic and pelvic CT scans
were performed, showing no abnormalities.
Discussion PEComas (Perivascular Epithelioid Cell Tumors) are mesenchymal-origin tumors with
typically benign behavior, although they have the potential for malignancy. Histologically,
they are characterized by epithelioid cells with perivascular growth and immunoreactivity
for melanocytic and smooth muscle markers. The occurrence of this pathology is rare,
and most individuals are asymptomatic, with incidental diagnosis found during imaging
studies or analysis of surgical specimens. Surgical treatment is the most common approach.
Conclusion Given the rarity of this condition and the limited data in the literature, further
studies are needed to establish the ideal management and treatment, especially for
malignant cases. Well-established diagnostic methods are crucial for the correct identification
of this entity and distinguishing it from other differential diagnoses.
