Resection material consisted of a minor labial fold and adjacent tissues measuring 4.5 x 2.8 x 1.5 cm, with 2 cm ulcerated nodular reddish lesion that microscopically revealed a papillary tumor, reminiscent of a colonic adenocarcinoma. The neoplastic epithelium was in continuity with the surface epidermis (Figure 1). The tumor was composed of papillary and complex glandular structures lined by large columnar cells with hyperchromatic nuclei. Many cells were containing intracytoplasmic mucin and rare goblet cells were seen (Figure 2). The depth of invasion was measured as 0.8 cm. Lateral and deep margins were free of tumor. Intracytoplasmic mucin was demonstrated with staining for Alcian blue histochemistry. Immunohistochemical analysis exhibited diffuse positivity for cytokeratin 20, polyclonal CEA and CDX2 (Figure 3). Only focal positivity was seen for cytokeratin 7. No immunoreactivity was observed for WT-1 and GCDFP-15. Two of the 23 regional lymph nodes were metastatic with the tumor. The size of the metastatic focus was 15 mm in one of the positive lymph node and 2 mm in the other one. She did not receive adjuvant therapy. She is still alive and free of disease 38 months after surgery.

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Figure 1: Adenocarcinoma arising in direct continuity with surface epidermis (H&E; x20).

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Figure 2: Higher magnification shows complex glandular structures lined by large columnar cells with hyperchromatic nuclei and containing intracytoplasmic mucin (H&E; x40).

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Figure 3: Tumor cells show intranuclear staining for CDX2 antigen by immunohistochemistry (CDX2; x40).

Similar lesions can also be seen in vagina ¹². Although their origin is still the subject of speculation, the most commonly accepted notion is derivation from cloacal remnants, like vulvar lesions ¹². These lesions can occur anywhere in the vagina but are most common in the lower posterior vagina ¹². Exclusion of a metastasis to the vagina should also be undertaken before diagnosing a primary vaginal-type adenocarcinoma.

In our case, probable metastasis was excluded by PET scan and complete clinical workup. Detailed evaluation of the gastrointestinal tract, breast and lung showed no evidence of a primary tumor. Bartholin's or other gland adenocarcinoma was ruled out by the location of far from vestibule, close to the urethral meatus, and the absence of any native Bartholin's gland adjacent to the tumor. The final diagnosis was therefore cloacogenic mucinous adenocarcinoma with regard to the histopathological and immunohistochemical findings. Strong cytokeratin 20 and weak cytokeratin 7 expression favoured the diagnosis. Additional polyclonal CEA and CDX2 positivity was consistent with the diagnosis of colonic type adenocarcinoma as reported in the previous cases ^7,11.

The published reports on tumors developing from cloacogenic remnants within the vulva consist mainly of single case reports. Tiltman and Knutzen ⁴ reported the first case of cloacogenic adenocarcinoma and they mentioned that the cell origin of this adenocarcinoma was a misplaced cloacal remnant. After Tiltman, Lee et al. ⁵ reported a case of multicentric cloacogenic carcinoma of the perianal skin and vulva. Kennedy and Majmudar ⁶ published two cases of primary adenocarcinomas of vulva and repeated that the possible origin was cloacal structures. Furthermore, Willen et al., Zaidi and Conner, Liu et al. and Dube et al. presented case reports of primary vulvar cloacogenic adenocarcinomas ^7-10. Cloacogenic-derived adenocarcinomas are most often seen in postmenopausal women, but premenopausal cases have been reported ⁸. The mean age of the patients reported was 51 years (range between 38-63 years). In the majority of these cases, tumors ranged in size from 1 to 2 cm largest diameter. In all the cases described, the clinical behavior of this rare tumor was quite indolent and overall survival was excellent after radical vulvectomy or wide total excision. Bilateral inguinal lymph node dissection has been performed in four of the reported cases ^4,8-10 and only one showed ipsilateral metastasis ⁴. In our case, metastatic adenocarcinoma was found in two of bilateral inguinal lymph nodes sampled. Therefore, in our opinion, ipsilateral or bilateral inguinal lymph node dissection is indicated. The summary of clinical features and management of these patients can be seen in Table I.

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Table I: Clinical features and outcome of 10 patients

In conclusion, knowledge of cloacogenic vulvar adenocarcinomas is very limited due to the small number of cases. A cloacogenic origin should be considered in intestinal-like or mucinous neoplasms. Nodal metastasis should always be kept in mind both in clinical and pathological examination.

CONFLICT OF INTEREST
The authors declared no conflict of interest

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