Tongue Metastasis of Mucinous Colorectal Adenocarcinoma: Report of a Rare Case

Abstract

Metastases in the oral and maxillofacial region, particularly in soft tissues, are exceedingly rare. Such metastases can present as swelling in older individuals, especially in the tongue and gingiva. Furthermore, colorectal metastases at this site are commonly found in the mandible and gingiva and usually share the same morphology as the primary tumor. Herein, we report the case of a 61-year-old woman with a metastatic nodule in the tongue covered by normal mucosa. The clinical, histopathological, and immunohistochemical findings were essential for the final diagnosis of colorectal metastasis, consistent with adenocarcinoma with mucinous differentiation and intestinal phenotype. Metastases of colorectal adenocarcinoma to the tongue are rare but should be included in the differential diagnosis of nodular lesions at this site. The diagnosis can therefore be made based on meticulous clinical and histopathological examination complemented by immunohistochemistry.

We report here the case of a 61-year-old woman who was seen in June 2021 with a 4-month history of asymptomatic swelling on the tongue. Magnetic resonance imaging showed an expansive lobulated lesion with an intense T2 hypersignal (Fig. 1a). The results of an incisional biopsy were inconclusive. We thus decided to perform an excisional biopsy (Fig. 1b). Histopathological examination showed a nodular structure with abundant mucoid material dissecting the neoplasm (Fig. 1c-i). The nodule consisted of multiple cystic, generally papillary spaces, sometimes lined with pseudostratified columnar epithelium and mucous, and luminal cells with eosinophilic cytoplasm protruded into the lumen. Other areas were lined with cuboidal basal epithelium, short columnar, and overlying goblet cells. Thus, the diagnosis was well-differentiated mucinous nodular neoplasia. Immunohistochemistry was positive for CK7, CK20, CDX2, MUC2, MUC5, EMA, CEA, beta catenin, p53, p63, and Ki-67 and negative for AE1/AE3, CK5/6, SATB2, S100, and androgen receptor (Fig. 2). The final diagnosis was adenocarcinoma with mucinous differentiation and intestinal phenotype. In February 2022, the patient started to experience pain when evacuating, and recto-sigmoidoscopy revealed a rectum adenocarcinoma. The patient received chemo- and radiotherapy, and there are no signs of recurrence after two years.

Fig. 1.

(a) Axial MRI image showing an expansive and lobulated lesion with a T2 hypersignal on the tongue. (b) Intraoperative image obtained during the excisional biopsy showing the presence of an indurated swelling. (c) Pools of extracellular mucin dissecting the stroma. (d) Pools of extracellular mucin with focal accumulation of goblet cells; detail of goblet cells (inset). (e) Fibrous walls lined with mucinous epithelium and mucin on the right; detail of mucinous epithelium with basal columnar cells (inset). (f) Fibrous walls lined with mucinous epithelium and mucinous cells floating between extracellular mucin and extravasated blood cells; detail of floating mucinous cells. (g) Epithelial fragments floating in a pool of mucin, hemorrhagic content, and inflammatory response. (h) Mucinous glandular epithelium displaying mild atypia. (i) Primary adenocarcinoma found after recto-sigmoidoscopy displaying loss of stratification and hyperchromatic nuclei

Fig. 2.

Immunohistochemistry panel. Positivity for CK7 (a), CK20 (b), EMA (c), MUC2 (d), MUC5 (e), p63 (f), CDX2 (g), beta-catenin (h), and CEA (i). Positivity for p53 (j) was seen in focal areas and for Ki-67 (k) in 40% of neoplastic cells

The histopathological features of our case were consistent with adenocarcinoma with mucinous differentiation and intestinal phenotype. It was composed of a nodular structure characterized by abundant pools of acellular mucin dissecting the neoplasm, similar to what is seen in malignant tumors such as breast, colon, pancreas, biliary tract, appendix, and bladder cancer [1]. The neoplastic parenchyma exhibited multiple varying-sized cystic spaces with papillary structures lined with pseudostratified columnar epithelium and mucous and luminal cells with eosinophilic cytoplasm that protruded into the lumen, in addition to columnar and overlying goblet cells. Thus, our diagnostic hypotheses were primary intestinal-type adenocarcinoma of the tongue, mucinous adenocarcinoma of the salivary gland, and metastases. The morphological and immunohistochemical features favored adenocarcinoma with mucinous differentiation and intestinal phenotype, particularly due to positivity for CDX2, CK20, CK7, AE1/AE3, EMA, MUC5AC, and beta-catenin and negativity for other antibodies [2]. In the present case, the morphology was similar to that of the primary tumor. However, the latter was not mucinous.

Neoplastic endometrial gastrointestinal-type mucinous lesions are extremely rare [3]. Resembling our case, these lesions show intestinal differentiation and are positive for CK7, CEA, CK20, CDX2, PAX-8, and estrogen receptors [3]. We did not use the last two antibodies, but primary colorectal neoplasia supported our immunohistochemical results.

Salivary gland carcinoma, not otherwise specified, is characterized by varied histological subtypes, including intestinal variants often positive for CK20 and CDX2 [4]. The present case was negative for myoepithelial markers, supporting the diagnosis of primary colorectal neoplasia and the absence of a primary salivary neoplasm. Mucinous adenocarcinoma of salivary origin was also ruled out since this tumor is negative for CK20 and CDX2 [4, 5].

Metastases of colorectal adenocarcinoma to the tongue are rare but should be included in the differential diagnosis of nodular lesions at this site. The diagnosis can therefore be made based on meticulous clinical and histopathological examination complemented by immunohistochemistry.

Author Contributions

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by ACVPS and JNS. The first draft of the manuscript was written by ACVPS and JNS and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Funding

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Fundação de Amparo à Pesquisa do Estado da Bahia (FAPESB).

Data Availability

No datasets were generated or analysed during the current study.

Code Availability

Not applicable.

Declarations

Conflict of Interest

The authors declare no conflict of interest.

Ethical Approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Consent to Participate

Informed consent was obtained from all individual participants included in the study.

Consent for Publication

Consent for publication was obtained for every individual person’s data included in the study.

Competing Interests

The authors declare no competing interests.