Primary Intraosseous Adenoid Cystic Carcinoma with Widespread Skeletal Metastases Showing Features of High-Grade Transformation

Abstract

Malignant salivary gland carcinomas arising primarily within the jaw bones are extremely rare. The most common salivary malignancy in these locations is mucoepidermoid carcinoma followed by adenoid cystic carcinoma and adenocarcinoma. The clinical picture and imaging studies of these malignancies may be confused with odontogenic lesions which are more common in this location. Adenoid cystic carcinomas have a prolonged clinical course, tendency for perineural invasion and distant metastasis and multiple recurrences. The diagnosis of these tumors requires thorough histopathologic examination. Immunohistochemical studies may be required in cases showing solid growth pattern. High-grade transformation, earlier termed as dedifferentiation, has been observed in several salivary gland carcinomas including adenoid cystic carcinoma. These transformed tumors are reported to have an extremely poor prognosis. Here, we report a case of primary intraosseous adenoid cystic carcinoma with extensive skeletal metastases which showed a negative staining with p63 and positive staining with CD117. The tumor had a predominant solid growth pattern with areas indicative of high-grade transformation. A negative p63 staining may indicate an incomplete or focal loss of abluminal layer and this is one of the criteria for high-grade transformation in adenoid cystic carcinoma.

Spindle Cell Variant of Ameloblastic Carcinoma: Another Example in a Japanese Male

“…Expression of actin and calponin, also myoepithelial markers, in ameloblastic carcinoma can be a potential diagnostic pitfall. In fact, exceptional cases of intraosseous myoepithelial tumors of the jawbone have been described in the past and recently [ 9 ], basaloid cellular morphology itself is reminiscent of some salivary gland-type tumors including adenoid cystic carcinoma forming cribriform or pseudoglandular structures [ 2 ]. However, appropriate judgements can be made on the basis of an accurate and comprehensive understanding of every condition including the expression of other myoepithelial markers.…”

Primary cutaneous adenoid cystic carcinoma: a clinicopathologic, immunohistochemical, and fluorescence in‐situ hybridisation study of 13 cases

“…15 Approximately 56 cases of ACC with HGT have been recognised in the English literature to date. 15,18,21,[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] The most commonly involved sites by HGT were the submandibular gland and paranasal sinus, followed by the parotid gland and palate. 'HGT' is characterised by a distinct population of anaplastic cells with loss of the biphasic ductal-myoepithelial differentiation, clearly separated from conventional ACC.…”

“…in 1999 15 . Approximately 56 cases of ACC with HGT have been recognised in the English literature to date 15,18,21,34–49 . The most commonly involved sites by HGT were the submandibular gland and paranasal sinus, followed by the parotid gland and palate.…”

Bioinformatics identification of the candidate microRNAs and construction of a competing endogenous RNA regulatory network in lacrimal gland adenoid cystic carcinoma high‑grade transformation

“…As effective diagnostic and treatment strategies have not been developed, the prognosis of patients with LACC remains poor, mostly due to local or distant metastasis and recurrence. Lacrimal gland carcinomas with HGT have been shown to be more aggressive compared with conventional carcinomas with a poorer prognosis, accompanied by higher local recurrence rate and propensity for cervical lymph node metastasis (27). However, the molecular genetic mechanisms responsible for the pathway of HGT in lacrimal gland carcinomas largely remain to be elucidated.…”