BACKGROUND: High-grade transformation Adenoid cystic carcinoma (HGT-AdCC) of the parotid gland is a rare transformation noted in slow growing low grade AdCC. Perineural invasion and spread is an important feature of this tumor. Temporal bone involvement is rare. A total of only 10 cases of HGT-AdCC in parotid gland has been reported in literature so far predominantly in the elderly with peak incidence in 5th-6th decade.
METHODS: We present a young lady of HGT-AdCC of right parotid gland with temporal bone involvement in the form of isolated perineural invasion (PNI) of facial nerve till the tympanic segment. She underwent right radical parotidectomy with modified radical neck dissection with modified lateral temporal bone resection and pectoralis major myocutaneous flap reconstruction. Histopathological examination revealed both low- and high-grade areas. Sections from facial nerve showed tumor invasion.
CONCLUSIONS: The radiological features of isolated perineural spread in intratympanic part of facial nerve can be easily missed if not specifically looked for. Every attempt should be made preoperatively and intraoperatively to determine the complete extent of the tumor for adequate disease clearance. A combined clinico-radiological approach aided by histopathology examination helps in early detection of this carcinoma and in better patient management.

Adenoid cystic carcinoma (ACC) is a rare malignant cancer that arises from secretory glands. Slow growth, perineural invasion, and late recurrences are the main characteristics of ACC. Only few cases of kidney metastases from ACC have been reported in the literature. We report here the case of a 66-year-old female patient who presented with bilateral renal metastases from ACC of the nasal cavity, detected 14 years after treatment of primary tumor and 6 years after metastasectomy of lung metastases. Histological examination confirmed diagnosis and the patient was treated with systemic chemotherapy. Radiological evaluation showed stability of the disease. However, a progression with occurrence of metastases in other sites (lung and bones) has been observed after 7 months. She is still receiving second-line chemotherapy. To the best of our knowledge, this is the second case of kidney metastases from ACC of the nasal cavity.

BACKGROUND: Breast adenoid cystic carcinoma (AdCC) is a rare invasive carcinoma composed of epithelial and myoepithelial cells. Microglandular adenosis (MGA) is a rare benign proliferative lesion consisting of small, uniform, and round glands formed by a single layer of epithelial cells and basement membrane without a myoepithelial cell layer. MGA may progress to atypical MGA and carcinoma arising in MGA. Among various invasive carcinomas from MGA, AdCC has been rarely reported. Here, we report a case of AdCC arising in MGA.
METHODS: A 59-year-old woman was diagnosed with a newly developed density on a routine mammogram. The density was similar to or slightly lower than that of the breast parenchyma. Sonography showed an irregular mass with a slightly higher echo than that of fat. Magnetic resonance imaging showed an irregular mass with a similar T1 signal intensity and a slightly higher T2 signal intensity compared to muscles or the breast parenchyma. The lesion showed heterogeneous internal enhancement with an initially slow and delayed persistent enhancing pattern. Microscopically, the tumor was composed of invasive AdCC, in situ AdCC, and MGA. AdCC is composed of basaloid and ductal epithelial cells forming cribriform or solid sheets, or haphazardly scattered small cribriform or tubular glands. MGA showed small glands with a single epithelial lining and retained lumen. S-100 staining was strongly positive in MGA area. The patient underwent breast-conserving surgery with sentinel lymph node biopsy.
CONCLUSIONS: Breast AdCC arising in MGA showed unique imaging findings that was different from usual invasive cancer.

In the oral cavity, adenoid cystic carcinomas of the buccal mucosa are extremely rare. Minor salivary grand adenoid cystic carcinoma should receive aggressive treatment to achieve negative surgical margins to inhibit recurrence.

The purpose of this study was to suggest general guidelines in the management of the N0 neck of oral cavity and oropharyngeal adenoid cystic carcinoma (AdCC) in order to improve the survival of these patients and/or reduce the risk of neck recurrences. The incidence of cervical node metastasis at diagnosis of head and neck AdCC is variable, and ranges between 3% and 16%. Metastasis to the cervical lymph nodes of intraoral and oropharyngeal AdCC varies from 2% to 43%, with the lower rates pertaining to palatal AdCC and the higher rates to base of the tongue. Neck node recurrence may happen after treatment in 0-14% of AdCC, is highly dependent on the extent of the treatment and is very rare in patients who have been treated with therapeutic or elective neck dissections, or elective neck irradiation. Lymph node involvement with or without extracapsular extension in AdCC has been shown in most reports to be independently associated with decreased overall and cause-specific survival, probably because lymph node involvement is a risk factor for subsequent distant metastasis. The overall rate of occult neck metastasis in patients with head and neck AdCC ranges from 15% to 44%, but occult neck metastasis from oral cavity and/or oropharynx seems to occur more frequently than from other locations, such as the sinonasal tract and major salivary glands. Nevertheless, the benefit of elective neck dissection (END) in AdCC is not comparable to that of squamous cell carcinoma, because the main cause of failure is not related to neck or local recurrence, but rather, to distant failure. Therefore, END should be considered in patients with a cN0 neck with AdCC in some high risk oral and oropharyngeal locations when postoperative RT is not planned, or the rare AdCC-high grade transformation.

The primary treatment for head and neck adenoid cystic carcinoma (ACC) is surgery. Infrequently, however, ACC\'s propensity for perineural and base of skull invasion can preclude definitive surgical management. We present our experience with proton radiation therapy (RT) and concurrent platinum-based chemotherapy.
Nine patients with unresectable node-negative, nonmetastatic head and neck ACC received definitive proton RT and concurrent cisplatin. Outcomes and toxicities were recorded. A systematic review of the literature was performed.
Median follow-up was 27 months (range, 9.2-48.3 months). Four patients achieved complete response at the primary site, and an additional 4 patients achieved stabilization of local disease. Only 1 patient developed local disease progression. Four patients had 5 acute grade 3 (G3) toxicities, and 1 patient developed a chronic G4 optic nerve disorder.
Our preliminary results suggest proton RT and concurrent chemotherapy is a definitive treatment option for select patients with head and neck ACC. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1472-E1480, 2016.

Adenoid cystic carcinomas are deceptive malignancies that show slow growth and local invasion with recurrences seen many years after diagnosis. Upto 50% of these tumors occur in the intraoral minor salivary glands usually in the hard palate. Buccal mucosal tumors are relatively rare. We determined the incidence of buccal mucosal adenoid cystic carcinoma by reviewing the number of reported cases in the literature. This is the first article to analyze the occurrence of adenoid cystic carcinomas in the buccal mucosa through a review of 41 articles. Our review revealed 178 buccal mucosal adenoid cystic carcinomas among a total of 2,280 reported cases. We present a case of adenoid cystic carcinoma occurring in the left buccal mucosa of a 45-year-old female.