Akihiko Ohno

Mucinous adenocarcinoma of the submandibular gland

A rare tumor not easily classifiable among published histologic categories for salivary gland tumors is reported. The neoplasm developed within the submandibular gland of a 78‐year‐old woman with invasion of the mandible and metastasis to regional lymph nodes. Histopathologically, cuboidal cells possessing clear cytoplasm and displaced round nuclei proliferated and exhibited an adenomatous pattern. Many cystic spaces surrounded by tumor cell strands were seen, mucus substance filled in the cystic spaces, and the tumor cells seemed mucus‐secreting, but neither epidermoid cells nor papillary appearance could be observed. Electromicroscopically, numerous mucous droplets of low electron density were prominent in the cytoplasm, and the tumor cells had sparce irregular microvilli on the luminal surface. Mucin histochemistry, including paradoxical concanavalin A staining, revealed that the tumor cells contained neutral and acid mucins, and these were identified as class II and III mucosubstances. No other neoplastic lesion, except recurrent metastatic neck nodes, has been detected 6 years after the first examination, and it seems that the tumor is a rare primary mucinous adenocarcinoma of the submandibular gland.

Thyroid carcinomas found incidentally in the cervical lymph nodes: do they arise from heterotopic thyroid tissues?

PURPOSE Thyroid carcinomas have been found incidentally in the cervical lymph nodes during surgery for head and neck squamous cell carcinoma (SCC). Such carcinomas have been considered a metastatic focus for malignant transformation of heterotopic thyroid tissue. We report on cases of so-called occult thyroid carcinoma in the cervical lymph nodes, and review the relevant literature. PATIENTS AND METHODS We encountered 3 cases of incidental papillary carcinoma in the cervical lymph nodes of patients with oral SCC, and consequently reviewed 75 previously reported cases. RESULTS Among 148 patients with oral SCC who had undergone cervical lymph node dissection, 3 were diagnosed with occult thyroid carcinoma. Papillary carcinomas were found in 3, 10, and 3 lymph nodes in cases 1, 2, and 3, respectively. Computed tomography showed 2 tumor-like shadows and 1 calcified mass in the thyroid gland in cases 2 and 3, respectively. These shadows did not enlarge during the 3 to 5 years of observation, and all patients are alive, without any events related to the neck and thyroid gland. Among the reviewed cases, approximately two fifths were histopathologically or clinically free from thyroid carcinoma. Progressive thyroid carcinoma was not detected in any patient. CONCLUSIONS We propose the possibility that thyroid carcinoma in the cervical lymph nodes is not necessarily metastatic, but may occasionally arise from heterotopic thyroid tissue.

Radicular Cysts in the Mandible with Ciliated Columnar Epithelial Lining — Report of 3 Patients Including Keratin Expression Findings

Abstract Objective: To examine 3 radicular cysts, which appeared to be atypical glandular odontogenic cysts. Patients and Methods: Histological and immunohistochemical investigation of 3 extirpated radicular cysts of 3 patients, using cytokeratin 13 and 18 expression was performed and the findings compared with those of normal oral epithelium, radicular cyst, and postoperative maxillary cyst. Results: The cysts were lined with ciliated columnar epithelium with a few mucicarmine positive cells. None of the cyst linings contained papillary projections, crypt-like depression, and luminal epithelial plaques, which are characteristic of glandular odontogenic cysts. Immunohistochemically, the 3 cyst linings were positive for cytokeratin 18 and cytokeratin 13, although the cytokeratin 13 expression intensity varied from strong to weak. Cytokeratin 18 was expressed on the upper layers, while cytokeratin 13 was expressed in the middle layers. Conclusion: From these clinical and histological appearances, the 3 cysts were regarded as glandular odontogenic cysts although they are not typical for glandular odontogenic cysts.