Report of a case of acinic cell carcinoma of the upper lip and review of Japanese cases of acinic cell carcinoma of the minor salivary glands

Abstract

Acinic cell carcinoma (ACC) is a malignant tumor of the salivary glands. The majority of ACCs occur in the parotid gland, and ACCs of the minor salivary glands (MSGs) are relatively infrequent. We describe here a patient with ACC of the upper lip. The patient was a 31-year-old male who presented with a nodular mass on the left upper lip. The preoperative diagnosis was benign tumor or cyst, and the lesion was surgically excised. The histological diagnosis was ACC. The postoperative course was uneventful. No recurrence or metastasis was detected at 13 months postoperatively. In addition, we retrospectively reviewed 21 reported Japanese patients with ACC of the MSGs. In 7 of the 21 patients, the preoperative diagnosis was benign tumor, and the tumors were resected without preoperative biopsy. Kaplan–Meier analysis showed that disease-free survival was worse in patients who underwent resection with a preoperative diagnosis of benign tumor than in patients who underwent resection with a preoperative diagnosis of malignant tumor. The rate of recurrence was higher for ACCs assumed to be benign lesions on a purely clinical basis, or without an accurate preoperative biopsy. ACCs of the MSGs are easy to be misdiagnosed for benign lesions such as mucous cysts or hemangiomas. Correct preoperative diagnosis and initial therapy may therefore be the most important prognostic factors. Key words:Acinic cell carcinoma, Kaplan-Meier analysis, minor salivary glands, prognosis, upper lip.

Factors influencing delayed referral of oral cancer patients from family dentists to the core hospital

“…In contrast, smaller OC lesions may be difficult to recognize for family dentists with no specialization in oral surgery, as these smaller lesions generally mimic the characteristics of benign lesions. 17 , 18 , 25 , 26 Moreover, patients with smaller OC lesions generally do not experience any symptoms, 16 and patients with OC may have little knowledge of the disease. 27 , 28 Thus, patients with smaller OC lesions may not present with any complaints.…”

“…We hypothesized that the dentists' familiarity with gingival examinations also makes them accustomed to seeing severe gingival inflammation. Since gingival inflammation and malignancy are often similar in appearance, 17 , 18 , 25 family dentists may have a high threshold for the diagnosis of gingival malignancy, and they may diagnose a malignant gingival lesion as gingival inflammation, leading to prolonged referral delays. However, in the present study, the gingival site of OC was not a significant risk factor for referral delays.…”

“…Furthermore, OC in the initial stage may mimic benign lesions. 17 , 18 Unfortunately, even general dental practitioners and family dentists may find it difficult to distinguish early-stage OC from benign lesions. 11 , 12 Most family dentists in Japan see only a very limited number of OC cases over the course of their careers.…”

A challenging diagnosis of a mucocele in the maxillary gingiva: Case report and literature review

“…Cho et al reported a case of acinic cell carcinoma that presented as an asymptomatic mucocele-like mass on an unusual site, the lower lip; after a clinical and histopathological diagnosis of acinic cell carcinoma, they performed surgical excision with a safety margin [ 6 ]. Ishikawa et al also reported a case of acinic cell carcinoma of the upper lip: the preoperative diagnosis was benign tumor or cyst, and the mass was thus surgically excised along the border with the normal tissues [ 7 ]. A case of mucoepidermoid carcinoma in which the clinical and radiographic investigations were suggestive of a mucocele (ranula) was described by Melo et al [ 8 ] The treatment of choice was the complete excision of the mucocele and left submandibular salivary gland.…”