Primary clear cell carcinoma of the vulva: A case report

Abstract

Clear cell carcinoma (CCC) of the vulva is extremely rare. We report a case of a 54-year-old woman who presented with a 5 cm mass of the mons pubis. She underwent needle biopsy demonstrating CCC. She then underwent radical vulvectomy with bilateral inguinofemoral lymph node dissection. Surgical pathology revealed CCC of the vulva with lymphovascular space invasion (LVSI) and metastatic carcinoma in 1/7 inguinal lymph nodes. The patient has a history of endometriosis, raising suspicion that her CCC could have arisen from endometriosis in the mons. She completed adjuvant treatment with cisplatin and concurrent external beam radiation therapy with radiographic evidence of complete response. However, short-interval imaging demonstrated multi-focal recurrence, which was confirmed with supraclavicular lymph node biopsy. She then completed 8 cycles carboplatin, paclitaxel, and biosimilar bevacizumab-bvzr with favorable response on imaging. She was continued on bevacizumab maintenance. She was later started on pembroluzimab for disease progression based on new mediastinal adenopathy and worsening retroperitoneal lymphadenopathy. She received eight cycles of pembrolizumab with ongoing disease progression before enrolling in hospice and discontinuing cancer-directed treatment. As described in the related literature which we summarize here, the majority of reported cases of vulvar CCC arise from endometriosis implants at the site of prior episiotomy or from the Bartholin's gland. This patient had clinical history of endometriosis; prior tissue sampling was not performed to support the diagnosis. Given the absence of data regarding this rare type of primary vulvar cancer, treatment of this patient's disease was based on existing data specific to squamous cell carcinoma of the vulva and extrapolated from treatment guidelines for CCC of the ovary and endometrium. Continued research is needed on this rare form of vulvar carcinoma to determine the risk factors, prognostic factors, and treatment recommendations specific to this disease.

Keywords: Clear cell carcinoma of vulva; Endometriosis; Episiotomy; Vulvar carcinoma.

Fig. 1

MRI pelvis demonstrating a heterogenous vulvar mass centered in the subcutaneous soft tissue of the vulva, measuring 5.2 × 4.4 × 5.7 cm with intermediate high T2 signal and internal hyperenhancement with restricted diffusion (A and B). PET/CT shows a soft tissue density mass in the mons pubis, measuring 6.7 × 4.2 cm transverse by 6.5 cm craniocaudal with SUV max 10.3 g/mL (C), a right inguinal lymph node measuring 1.4 × 1.1 cm with SUV max 4.2 g/mL (D), and retro-aortic lymph node measuring 1.6 × 1.0 cm with SUV max 3.6 g/mL, which was slightly greater than blood pool background (E).

Fig. 2

Clinical appearance of the mons pubis mass with ulceration through the skin at inferior edge of tumor on day of surgery (A), and post-resection appearance of vulva (B).

Fig. 3

Gross appearance of tumor (A). Histological sections show papillary and solid architecture, moderate to high-grade nuclear atypia, and clear to eosinophilic cytoplasm (B). Immunohistochemistry (IHC) positive for Napsin A, HNF1 beta, AMACR, and negative for ER. ARID1A was lost (abnormal). PD-L1 IHC showed a Combined Positive Score (CPS) of 5, mostly due to expression in mononuclear inflammatory cells, with very rare positive tumor cells (C).

Fig. 4

Short-interval post-treatment PET/CT showed multifocal recurrence pattern, a sample of which are included here. (A) Enlarged left supraclavicular lymph node measuring 1.9 × 1.2 cm with SUV max of 5.2 (B) Right retrocaval lymph node measuring 1.9 × 2.3 cm with SUV max of 8.4, previously 1.2 × 1.3 cm with SUV max of 3.7 (C) New aortocaval node measuring 2.2 × 1.5 cm with SUV max of 8.6. (D) Mesenteric soft tissue nodule measuring 3.5 × 1.6 cm with SUV max of 8.2, previously 1.5 × 1.2 cm with SUV max of 5.9. There is surrounding misty mesentery.