Mature ovarian teratomas, frequently known as dermoid cysts, represent one of the most common benign ovarian tumors, accounting for approximately 10–25% of all ovarian neoplasms. These tumors arise from pluripotent germ cells and characteristically contain differentiated tissues originating from one or more embryonic germ layers: ectoderm, mesoderm, and endoderm. Mature teratomas typically present as asymptomatic adnexal masses, often incidentally discovered during routine pelvic examinations or imaging studies. However, they occasionally present clinically with complications, such as torsion, rupture, or secondary infections, manifesting as acute or subacute pelvic pain [1-3]

A unique histopathologic feature occasionally noted in mature ovarian teratomas is the "pneumatosis cystoides-like appearance," characterized by multiple cystic spaces within the tumor wall, accompanied by granulomatous inflammatory reactions involving macrophages and multinucleated giant cells. Despite being relatively common within teratomas, this distinct feature remains underreported and is rarely comprehensively documented in the medical literature [4-5].

In this report, we describe the clinical and pathological findings of a 55-year-old female who presented with unilateral pelvic pain, progressively worsening over one week. Ultrasonographic imaging revealed a cystic mass in the right ovary, measuring approximately 74×45 mm, containing echogenic components    and    associated   with    a   bulky uterus. Surgical management via total laparoscopic hysterectomy identified an enlarged cystic right ovary, filled with characteristic yellowish-white sebaceous material, tufts of hair, and calcified, bony-hard areas suggestive    of a     Rokitansky   nodule.    Histopathologic examination of the lesion revealed features consistent with mature ovarian teratoma exhibiting a pneumatosis cystoides-like pattern, matching descriptions previously reported in the literature.

By elucidating this unusual histopathologic finding, this report seeks to enhance clinical recognition of pneumatosis cystoides-like features within ovarian teratomas, underscore their benign nature, and facilitate differentiation from other, potentially more aggressive, ovarian lesions.

Case Description

A 55-year-old female presented to the gynecological outpatient department with complaints of gradually worsening unilateral pelvic pain on the right side over a duration of one week. The pain was characterized as dull and aching in nature, primarily localized to the lower abdomen and pelvic region, without radiation to other areas. The patient denied associated symptoms such as fever, nausea, vomiting, urinary disturbances, or abnormal vaginal bleeding. Her medical and surgical histories were unremarkable, with no previous similar episodes reported. She had regular menstrual cycles until menopause three years earlier, and she had no significant family history suggestive of malignancy or ovarian disorders.

On clinical examination, the abdomen was soft with mild tenderness in the right lower quadrant. No palpable masses were detected upon abdominal palpation. Pelvic examination similarly revealed mild tenderness on palpation of the right adnexal region; however, no definitive mass was palpated during the physical examination.

Pelvic ultrasonography revealed a well-defined cystic mass arising from the right ovary, measuring approximately 74 mm×45 mm. The lesion displayed internal echogenic areas consistent with calcifications or fatty tissues, highly suggestive of a mature ovarian teratoma. Additionally, the uterus was observed to be slightly bulky; however, there were no other abnormal findings or lesions identified in the uterus or left ovary.

In light of the clinical and ultrasonographic findings, surgical management was pursued. The patient underwent a total laparoscopic hysterectomy with bilateral salpingo-oophorectomy. Intraoperative examination confirmed the enlargement of the right ovary, which appeared cystic and filled with characteristic yellowish-white sebaceous material, clusters of hair, and firm, calcified areas indicative of a Rokitansky nodule. No adhesions, evidence of torsion, rupture, or hemorrhage were identified intraoperatively.

Histopathological evaluation of the surgical specimen revealed findings consistent with a mature cystic ovarian teratoma exhibiting a pneumatosis cystoides-like appearance. The cystic wall contained multiple cystic spaces of variable sizes lined by mononuclear histiocytes and multinucleated giant cells with abundant foamy cytoplasm, representing a foreign-body granulomatous reaction. Immunohistochemical analysis further confirmed the granulomatous origin, with positive staining for CD68 markers. The cystic spaces lacked epithelial lining, and no atypical cells or signs suggestive of malignancy were observed.

The patient’s postoperative recovery was smooth and uneventful, with hospital discharge occurring on the third postoperative day. Subsequent follow-up visits at one month and three months post-surgery revealed a complete resolution of symptoms, with no postoperative complications or recurrence of pain noted.

Mature cystic ovarian teratomas are common benign ovarian tumors, typically encountered in reproductive-age women but occasionally seen in postmenopausal individuals [6-8] In our presented case, the patient was a 55-year-old postmenopausal woman who presented with unilateral pelvic pain, a clinical scenario less frequently documented in the literature compared to asymptomatic presentations typically associated with mature cystic teratomas. The clinical presentation with acute or subacute pelvic pain often raises concern for potential complications such as torsion, rupture, or secondary inflammation. However, intraoperative findings in our patient revealed no evidence of these complications, suggesting the possibility of intermittent ischemic episodes or subtle mechanical irritations contributing to symptom development.

An important and distinguishing histopathologic finding in this case was the pneumatosis cystoides-like appearance. This distinctive but underreported histological feature is characterized by multiple cystic spaces within the tumor wall, surrounded by granulomatous inflammation composed of histiocytes and multinucleated giant cells. The histological assessment in our patient clearly demonstrated cystic spaces of variable sizes lined by mononuclear histiocytes and multinucleated giant cells exhibiting foamy cytoplasm. Immunohistochemical analysis further substantiated these findings, confirming positivity for the histiocytic marker CD68, which indicated a foreign-body granulomatous response. The absence of epithelial lining within these cystic spaces and the lack of malignant cells further reinforced the benign nature of this lesion.

The precise etiology of pneumatosis cystoides-like changes within mature ovarian teratomas remains unclear, and several hypotheses have been postulated. The granulomatous reaction observed in our case likely represents a histiocytic response to the extravasation of sebaceous or fatty material originating from within the cyst into the surrounding stroma, a theory supported by similar findings reported in prior studies.^9,10 Another potential mechanism is transient ischemia, possibly caused by intermittent ovarian torsion or subtle mechanical compression, contributing to focal weakening of the cyst wall and subsequent leakage of cyst contents into adjacent tissues. Although overt torsion was absent in our patient, the rapid onset and progression of symptoms support the plausibility of subtle ischemic or mechanical processes being involved [4,5,11]

Recognizing the pneumatosis cystoides-like pattern within mature ovarian teratomas has significant diagnostic implications. This histologic feature can present diagnostic challenges, particularly if typical teratomatous elements such as squamous epithelium, hair, or teeth are minimal or absent. In such situations, familiarity with this histologic presentation can be pivotal, providing diagnostic clarity and preventing unnecessary extensive surgical procedures or overtreatment [4,5,12]. In our patient, the characteristic histological and immunohistochemical findings allowed a definitive benign diagnosis, facilitating straightforward surgical management and reassuring clinical outcomes.

Our case underscores the importance of comprehensive histopathological evaluation coupled with immunohistochemistry in accurately identifying pneumatosis cystoides-like patterns. It further emphasizes the benign and favorable prognosis of such lesions. The uneventful postoperative recovery and complete resolution of symptoms in our patient clearly reflect the benign behavior of mature ovarian teratomas exhibiting pneumatosis cystoides-like appearance.

In summary, awareness of pneumatosis cystoides-like appearance as a distinctive, benign histopathological feature in mature ovarian teratomas is crucial. Clinicians and pathologists must recognize and interpret this histologic entity accurately, as it significantly influences patient management decisions, prognosis discussions, and appropriate follow-up strategies.

The pneumatosis cystoides-like appearance observed in mature ovarian teratomas is a distinctive yet underreported benign histopathological finding. Accurate recognition of this unique pattern by both pathologists and clinicians is critical, as it aids in avoiding unnecessary interventions or misdiagnoses as more aggressive ovarian lesions. Awareness of this entity not only facilitates optimal patient management but also reassures patients regarding the benign nature and favorable prognosis associated with this specific histologic feature.

1. Cong, L. et al. "Mature cystic teratoma: an integrated review." International Journal of Molecular Sciences, vol. 24, no. 7, 2023, pg. 6141.

2. Sahin, H., Saliha Abdullazade, and Sanci, M. "Mature cystic teratoma of the ovary: a cutting edge overview on imaging features." Insights into Imaging, vol. 8, no. 1, 2017, pp. 227–241.

3. Radiopaedia.org. "Mature cystic ovarian teratoma." Available from: https://radiopaedia.org/articles/mature-cystic-ovarian-teratoma-1.

4. Litos, M. et al. "Pneumatosis cystoides-like histopathologic appearance in a mature ovarian teratoma." Medeni Medical Journal, vol. 36, no. 2, 2021, pp. 163–166.

5. Mathew, M., Goel, G., and Kumar, P. "A diagnostic curiosity: mature cystic teratoma of the ovary with pneumatosis cystoides-like appearance: case report and review of literature." Internet Journal of Gynecology and Obstetrics, vol. 11, no. 2, 2008, pp. 1–3.

6. Quraishi, A.H., Siba Kumar Jena, and Umare, G. "An unusual and rare presentation of mature cystic teratoma in a post-menopausal woman: a case report." International Surgery Journal, vol. 10, no. 1, 2023, pp. 165–167.

7. Wu, R.T. et al. "Mature cystic teratoma of the ovary: a clinicopathologic study of 283 cases." Chung Hua I Hsueh Tsa Chih (Taipei), vol. 58, no. 1, 1996, pp. 269–274.

8. Rim, S.Y., Sang Mi Kim, and Choi, H.S. "Malignant transformation of ovarian mature cystic teratoma." International Journal of Gynecological Cancer, vol. 16, no. 1, 2006, pp. 140–144.

9. Maudsley, G., and Zakhour, H.D. "Pneumatosis cystoides-like appearances in a mature cystic teratoma of the ovary." Histopathology, vol. 14, no. 4, 1989, pp. 420–422.

10. Canzonieri, V. et al. "Sieve-like areas in mature cystic teratomas of the ovary: a histochemical and immunohistochemical study of 7 cases." Pathologica, vol. 86, no. 1, 1994, pp. 43–46.

11. Cleveland Clinic. "Ovarian torsion." Available from: https://my.clevelandclinic.org/health/diseases/ovarian-torsion.

12. Wong, Y.P., and Tan, G.C. "The eyes do not see what the mind does not know: an underreported feature in mature cystic teratoma of the ovary." Medical and Health Journal, vol. 13, no. 2, Dec. 2018, pp. 223–228.