Mature ovarian teratomas, or dermoid cysts, are common benign ovarian tumors typically arising from pluripotent germ cells, characterized by tissues derived from embryonic germ layers. We present a rare case of a 55-year-old postmenopausal female who presented with unilateral pelvic pain, progressively worsening over one week. Ultrasound imaging identified a right ovarian cystic mass consistent with a mature teratoma. Surgical intervention via total laparoscopic hysterectomy and bilateral salpingo-oophorectomy revealed an enlarged cystic right ovary filled with sebaceous material, hair, and calcified Rokitansky nodules. Histopathology demonstrated a distinctive "pneumatosis cystoides-like" appearance characterized by multiple cystic spaces lined by histiocytes and multinucleated giant cells, confirmed by immunohistochemical positivity for CD68, signifying a granulomatous reaction. Awareness of this benign yet underrecognized histopathological pattern is essential to guide accurate diagnosis, prevent overtreatment, and reassure clinicians and patients of its favorable prognosis.