Accuracy of Preoperative MRI with Microscopy Coil in Evaluation of Primary Tumor Thickness of Malignant Melanoma of the Skin with Histopathologic Correlation

OBJECTIVE: The purpose of this study was to evaluate the accuracy of a preoperative MRI with microscopy coils in determining the primary tumor thickness of malignant melanoma with histopathologic correlation. MATERIALS AND METHODS: Eleven patients with histopathologically confirmed malignant melanoma were included in this study. MR images of the tumors were obtained with a 47-mm microscopy coil on 1.5T MR scanners and were evaluated by two radiologists, who assessed the thickness of the primary tumor on T2-weighted images (T2WI) and gadolinium-enhanced T1-weighted images with fat suppression (Gd-T1WI) and compared the results with the histopathologic findings as the reference standard. Correlations between tumor thickness on MRI and histopathologic examination were assessed using concordance correlation coefficients (CCCs). Inter- and intraobserver variabilities of tumor measurements were also assessed by intraclass correlation coefficient (ICC). RESULTS: Among the 11 cases included in the study, 10 cases from the same number of patients were managed with surgical excision and one case was confirmed with punch biopsy. The primary tumor thickness measured on T2WI showed better correlation with histopathologic results, as compared with measurements taken on Gd-T1WI: the CCC of measurements on T2WI ranged from 0.64 to 0.78, indicating a substantial agreement, whereas the CCC of measurements on Gd-T1WI ranged from 0.50 to 0.61, indicating a moderate to substantial agreement. Inter- and intraobserver agreements of readers 1 and 2 were excellent for both T2WI and Gd-T1WI, with ICC ranging from 0.86 to 0.99. CONCLUSION: MR imaging with microscopy coils may be an accurate technique in the preoperative assessment of tumor thickness in malignant melanoma, especially on T2-weighted images.

Malignant Nodular Hidradenoma: A Case Report

Malignant nodular hidradenoma is a rare skin appendageal tumor, and its imaging findings have not been previously described. We experienced the case of a large malignant nodular hidradenoma of the left upper arm in a 71-year-old woman. MRI revealed a large, lobular, poorly circumscribed, soft tissue mass at the left upper arm, and the mass showed homogeneous enhancement. 18F-FDG PET/CT showed hypermetabolic activity in the left upper arm mass with a maximal standard uptake value of 19.

Primary Cutaneous Meningioma on the Scalp of an Infant: A Case Report

During childhood, meningioma is an uncommon tumor, and in infants, extracranial meningioma is very rare. We report a case of primary cutaneous menigioma occurring on the scalp of a ten-month-old girl.

MR Imaging of Sacrococcygeal Pilonidal Sinus

PURPOSE: The purpose of this study is to evaluate the characteristic MR findings of sacrococcygeal pilonidal sinus. MATERIALS AND METHODS: Eight MR images of pathologically proven sacrococcygeal pilonidal sinus were retrospectively reviewed [M: F = 7: 1; age range 9-41 (median, 17) years]. In all cases, a sacrococcygeal mass was present. Five of the eight patients experienced pain, and in three was discharge. MR findings were evaluated with regard to the location and extent of the lesion, and the presence of sinus or cyst, and the results were compared with the pathologic findings. RESULT: According to the clinical manifestations, each case was assigned to one of four groups: the first type (n= 3) showed dermal thickening with subcutaneous fatty infiltration of the ipsilateral natal cleft while pathologically, a follicular cyst with dermal fibrosis and multiple fatty lobules with fibrous septa were found to be present. In the second type (n = 3), fluid was observed in the sinus tract, while the pathologic findings demonstrated the presence of an abscess in this area. In the third type (n = 1), a cystic lesion with airfluid level was present; pathologically, an abscess was revealed. The fourth type (n = 1) showed only a low signal intensity sinus tract on both T1 and T2-weighted images, while the pathologic findings indicated the presence of hairs and follicles within the tract. CONCLUSION: The MR findings of sacrococcygeal pilonidal sinus depend on the clinical manifestation and include subcutaneous fatty infiltration, a sinus tract with or without fluid retention, and a cystic lesion with air fluid level. These findings could be helpful for differentiating between this and other sacrococcygeal lesions.