ABSTRACT
OBJECTIVES: Among the benign tumours of the parotid gland, basal cell adenoma (BCA) is far less common than pleomorphic adenoma (PA). MR features of BCA, including diffusion-weighted imaging and dynamic contrast-enhanced study, have not been previously described. Assessment of the crucial MR features of BCA appears to offer beneficial clues for distinguishing BCA from PA. METHODS: We retrospectively reviewed 14 BCAs and 179 PAs in the parotid gland, collected between March 2000 and May 2012, from the MRI database. RESULTS: Nearly half of the BCAs had cystic components. The average ratio of the maximum diameter of the cysts to the BCAs (cystic ratio) was 0.80 ± 0.11 [standard deviation (SD)]. The BCA cystic ratio was significantly higher (p = 0.00232) than that of PAs. The cystic ratio threshold was 0.65 between cystic BCA and cystic PA. Sensitivity and specificity were 76.5% and 100%, respectively. The average of the apparent diffusion coefficient (ADC) values of the 12 BCAs [1.24 ± 0.18 (SD) ×10(-3) mm(2) s(-1)] was significantly lower than that of the 151 PAs [1.86 ± 0.40 (SD) ×10(-3) mm(2) s(-1)] (p < 0.001) and also lower than that of the cystic PAs [1.83 ± 0.57 (SD) ×10(-3) mm(2) s(-1)] (p < 0.00495). The ADC threshold was 1.31 × 10(-3) mm(2) s(-1) between BCA and cystic PA, with sensitivity and specificity of 81.2% and 91.7%, respectively, and also the same threshold 1.31 × 10(-3) mm(2) s(-1) between BCA and PA, with sensitivity and specificity of 92.7% and 91.7%, respectively. Time-signal intensity curves (TICs) showed various patterns. CONCLUSIONS: A small cystic mass with well-circumscribed borders and slightly lower ADC value may suggest BCA, although TICs showed various patterns.
Subject(s)
Adenoma, Pleomorphic/diagnosis , Adenoma/diagnosis , Magnetic Resonance Imaging/methods , Parotid Neoplasms/diagnosis , Adenoma/pathology , Adenoma, Pleomorphic/pathology , Adolescent , Adult , Aged , Aged, 80 and over , Anatomy, Cross-Sectional/methods , Contrast Media , Diagnosis, Differential , Diffusion Magnetic Resonance Imaging/methods , Diffusion Magnetic Resonance Imaging/statistics & numerical data , Female , Humans , Image Enhancement/methods , Image Processing, Computer-Assisted/methods , Magnetic Resonance Imaging/statistics & numerical data , Male , Middle Aged , Parotid Neoplasms/pathology , Retrospective Studies , Sensitivity and Specificity , Young AdultABSTRACT
Benign epithelial inclusions are uncommonly found in lymph nodes, and ectopic breast tissue in axillary lymph nodes is particularly uncommon. The patient is a 48-year-old woman who had an adenoma of the nipple removed 10 years previously. A swollen lymph node with amorphous calcifications in a clustered distribution on mammogram was found in the left axilla. Fine needle aspiration cytology showed only cystic change. Excisional biopsy was performed and microscopic examination demonstrated that the node contained benign mammary epithelial and glandular inclusions, and no evidence of malignancy. Such cases will be increasingly found due to the widespread use of mammography screening and biopsy of axillary sentinel lymph nodes. Ectopic breast tissue in lymph nodes may be mistaken for malignant lesions. It is most important to identify correctly the epithelial inclusions in lymph nodes to prevent an erroneous diagnosis.
Subject(s)
Breast , Choristoma/pathology , Lymph Nodes/pathology , Lymphatic Diseases/pathology , Biopsy, Fine-Needle , Female , Humans , Middle Aged , Sentinel Lymph Node BiopsyABSTRACT
BACKGROUND AND PURPOSE: Salivary duct carcinoma (SDC) is regarded as a high-grade malignancy in the current classification of salivary gland neoplasms. The aim of our study was to describe the MR imaging features of SDC. METHODS: Nine patients with SDC underwent MR imaging study. The apparent diffusion coefficient (ADC) values of SDCs were measured from diffusion-weighted images. Time-signal intensity curves (TICs) of the tumors on dynamic MR images were plotted, and washout ratios were also calculated. TICs were divided into four types: type A, curve peaks <120 seconds after administration of contrast material with high washout ratio (> or =30%); type B, curve peaks <120 seconds with low washout ratio (<30%); type C, curve peaks >120 seconds; type D, nonenhanced. We correlated the MR findings of SDC with the pathologic findings. RESULTS: All tumors had ill-defined margins and showed low to moderately high signal intensity for contralateral parotid gland on T2-weighted images. The average of the ADC values of the SDCs was 1.16 +/- 0.14 [SD] x 10(-3)mm(2)/s. Seven of nine (78%) tumors had type B enhancement. On the other hand, six of nine (67%) tumors with rich fibrotic tissue also had type C enhancement. CONCLUSION: The findings of ill-defined margin, early enhancement with low washout ratio (type B), and low ADC value (1.22 x 10(-3)mm(2)/s) were useful for suggesting malignant salivary gland tumors. Although it was reported that type C enhancement was specific for pleomorphic adenoma, SDC frequently has type C-enhanced focus.