MRI appearance of clear cell hidradenoma

Apocrine hydroadenoma mimicking a Morton's neuroma: a rare differential diagnosis

A 62-year-old woman, with neuropathic pain and paresthesia in her right forefoot, showed a circumscribed soft tissue swelling on the sole between the second and third metatarsal. Ultrasound (US) imaging showed a well-defined lesion in the second intermetatarsal space, without vascularization sign at Power Doppler (PD). In the first hypothesis, these findings led to Morton's neuroma. Magnetic Resonance Imaging (MRI), demonstrated a dumbbell-shaped lesion between the II and the III metatarsal heads; it extended cranially to the subcutaneous fat of the dorsal slope. The MRI findings weren't compatible with a classic Morton's neuroma and were radiologically undetectable. The patient had a sub-total excisional biopsy. The anatomopathological features were specific to an apocrine hydroadenoma from an ectopic sweat gland. This rare pathology has not been previously described in the literature and it must be considered as a differential diagnosis due to the clinical presentation and the US appearance mimicking Morton's neuroma.

Fluid-fluid Levels in Musculoskeletal Tumor Imaging

Fluid-fluid levels result from the separation of two fluids of differing densities within a cavernous space with the boundary between the two layers running in a horizontal plane at 90 degrees to the direction of gravity. Magnetic resonance imaging is the most sensitive imaging modality to identify fluid-fluid levels. Although the most common bone lesions containing fluid-fluid levels are aneurysmal bone cyst and telangiectatic osteosarcoma, fluid-fluid levels can be observed in a wide variety of bone and soft tissue lesions. Therefore, fluid-fluid levels cannot be considered diagnostic of any particular type of tumor and the diagnosis should be made on the basis of other clinical, radiological and pathological findings. This article summarizes the pathophysiology and imaging characteristics of fluid-fluid levels and discusses the differential diagnosis of tumors with this imaging sign.

Malignant sweat gland tumor of breast arising in pre-existing benign tumor: A case report

BACKGROUND

Sweat glands belong to skin appendages. Sweat gland tumors are uncommon, especially when they occur as malignant tumors in the breast. We report a case of malignant sweat gland tumor of the breast, including imaging and pathological findings.

CASE SUMMARY

A 47-year-old woman visited our hospital with a non-tender palpable lesion in her left breast. The lesion had not shown changes for 10 years. However, it recently increased in size. Sonography showed a well circumscribed cystic lesion with internal debris and fluid-fluid level. Magnetic resonance imaging showed a well circumscribed oval mass with T1 hyper-intensity compared to muscle and T2 high signal intensity. There was a small enhancing mural component in the inner wall of the mass. The tumor was resected. Its pathologic result was a malignant transformation of benign sweat gland tumor such as hidradenoma. The lesion was treated with excision and radiation therapy. At 1-year follow up, there was no local recurrence or metastasis in the patient.

CONCLUSION

In the case of a rapid growing cystic mass in the nipple and subareola, it is necessary to distinguish it from a malignant sweat gland tumor.

MR Imaging of Mushroom-like Skin Adnexal Tumors in the Scalp: A Report of Two Cases

Few studies had been published regarding imaging findings of skin adnexal tumors. We experienced two giant cases of them with a characteristic mushroom-like growth pattern. MRI showed a circumscribed mushroom-like shaped mass extruding from the subcutaneous tissue with microcystic lesions. Although differentiation between benignancy and malignancy may be difficult by radiological examinations, MRI may be helpful to identify its origin and differentiate soft tissue tumors with skin adnexal tumors in having these imaging findings.

Clear Cell Hidradenoma: Characteristic Imaging Features on Ultrasonography, Computed Tomography, and Magnetic Resonance Imaging

OBJECTIVES

The purpose of this study was to evaluate the imaging features of clear cell hidradenoma on ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI).

METHODS

The radiologic and pathologic databases at 2 medical institutions were searched retrospectively from 2004 to 2016 to identify patients with a diagnosis of clear cell hidradenoma. Ultrasonographic, CT, and MRI features were described, and pathologic specimens were reviewed.

RESULTS

There were 5 female and 4 male patients. The mean patient age was 48.9 years (range, 28-70 years). Five patients underwent only US; 2 patients underwent only CT; 1 patient underwent both US and CT; and 1 patient underwent US and MRI. Most of the tumors were located primarily in the subcutaneous fat layer. The mean tumor size was 18.4 mm. On US, 6 masses had a heterogeneous echo texture, including an anechoic portion with protruding echogenic portions. Two masses had multiple septa in the anechoic portion. On color Doppler US, blood flow was both central and peripheral in 5 patients. All 3 cases seen on CT presented as a low-attenuation mass with an enhanced solid internal nodule. On MRI, the mass showed heterogeneous signal intensity on T2-weighted images and enhancement of the peripheral wall and internal solid component on contrast-enhanced T1-weighted images.

CONCLUSIONS

Clear cell hidradenoma is usually located in the subcutaneous fat layer, has a well-defined margin, appears as a cystic mass with an internal solid nodule, and occasionally has multiple septa on US, CT, and MRI.

Acute muscle strain injuries: a proposed new classification system

PURPOSE

To better define and classify acute muscle strain injuries.

METHODS

Historically, acute muscle strains have been classified as grade I, II and III. This system does not accurately reflect the anatomy of the injury and has not been shown to reliably predict prognosis and time for return to sport.

RESULTS

We describe an imaging (magnetic resonance or ultrasound) nomenclature, which considers the anatomical site, pattern and severity of the lesion in the acute stage. By site of injury, we define muscular injuries as proximal, middle and distal. Anatomically, based on the various muscular structures involved, we distinguish intramuscular, myofascial, myofascial/perifascial and musculotendinous injuries.

CONCLUSIONS

This classification system must be applied to a variety of muscle architectures and locations to determine its utility; additional studies are therefore needed prior to its general acceptance.

LEVEL OF EVIDENCE

V.

Benign hidradenoma: magnetic resonance and ultrasound features of two cases

Tumors of sweat gland origin are rare in the hand but should be considered in the differential diagnosis when certain imaging features are present. We present a case of nodular hidradenoma of the hand, with previously unreported magnetic resonance imaging features, and a further case in the thigh, both with ultrasound and histopathological correlation. The imaging literature of this tumor is reviewed, and its significance is discussed with respect to the current understanding of its malignant potential.

MRI appearance of multiple eccrine spiradenoma

Multiple eccrine spiradenoma is one of the rarest tumours of the sweat gland. We report a case of multiple eccrine spiradenoma that was distributed in several parts of the body. On MRI the lesions presented with multiple dispersive foci with clear circumferences in the cutis and the subcutaneous tissue. The lesions showed low signal intensity on T1 weighted images, and high signal intensity on short tau inversion recovery images. Although the signal intensities of the lesions were not characteristic in this patient, multiple eccrine spiradenoma should be included in the differential diagnosis of the lesions in the cutis and the subcutaneous tissue.

Musculoskeletal Lesions With Fluid-Fluid Level: A Pictorial Essay

A fluid-fluid level was identified in 11.2% of focal lesions of bone. Fluid-fluid levels are observed on cross-sectional imaging with either computed tomography (CT) or magnetic resonance (MR) imaging. They become apparent when a fluid collection containing substances of different density is allowed to settle, and when the plane of imaging is perpendicular to the fluid level. For instance, within a collection of blood, the cellular components will settle dependently, with the lower density plasma forming a layer superiorly. The difference in the density of these layers can be observed on CT imaging. With MR imaging, these layers will have different signal characteristics, allowing for visualization of the fluid-fluid level. The presence of fluid-fluid levels within a musculoskeletal lesion is an important finding, which can significantly aid in the differential diagnosis. This finding can be observed in a wide variety of lesions: osseous and soft tissue masses, neoplastic or nonneoplastic lesions, malignant or benign neoplasms, and primary or metastatic malignancies. When a fluid-fluid level is detected, in conjunction with clinical history, the differential diagnosis for a lesion can often be limited to a few choices. For this reason, it is important to be aware of the multiple lesions that can produce fluid-fluid levels, as well as their differentiating characteristics and typical presentations. We will review both osseous and soft tissue lesions, focusing on their imaging characteristics and other important findings.

Imaging of sports-related muscle injuries

Muscle derangements in athletes have a wide variety of causes, treatments, and prognoses. Given that the cause and severity of sports-related injuries may be difficult to determine clinically in some cases, MR imaging is utilized increasingly to evaluate muscle injuries in athletes. After reviewing useful MR imaging techniques, this article focuses on MR imaging of the most common causes of muscle pain and disability in athletes, including myotendinous strain, delayed onset muscle soreness, muscle contusion, myositis ossificans, muscle laceration, muscle herniation, and compartment syndrome. The differential diagnosis of various signal intensity abnormalities in muscle also is reviewed.