Pure muscle tenosynovial giant cell tumor mimicks a metastasis in patient with melanoma

Tenosynovial Giant Cell Tumor (TGCT) is a rare benign synovial tumor arising from the tendon sheath, bursae, synovium or adjacent soft tissue. TGCT typical occurs in intra-articular site but can be rarely extra- articular. A 50-years-old woman already affected by malignant melanoma was submitted to PET/CT scan for routine diagnostic examinations during follow up; an intense FDG focal uptake corresponding to peritrochanteric medial part of right iliopsoas muscle was detected. Corresponding MRI images demonstrated a lesion with well-defined margins, slightly hyperintense in T1, low to intermediate signal intensity in T2 weighted scans, no significant restriction in DWI, and intense enhancement in T1 after intravenous contrast medium administration. There wasn’t evidence of extra-lesional spread. MRI findings oriented for benign lesion, but according to intermediate signal intensity in T2, intense enhancement in T1 after intravenous contrast medium, the presence of intense FDG uptake as well as history of aggressive malignancy, a local excision was done; then the final diagnosis of TGCT has been proven. Our case shows TGCT lesions may reproduce malignant appearance on FDG-PET, while MRI may be useful tool to properly manage affected patients. Keywords: Tenosynovial giant cell tumor; Melanoma metastasis; Diffusion-MRI; FDG-PET/CT.

Retro-Odontoid Pseudotumor Associated with Rheumatoid Arthritis

Retro-Odontoid Pseudotumor (ROP) commonly labeled as “pannus” is a non-neoplastic soft tissue mass adjacent to the odontoid process of C2 that is frequently associated with rheumatoid arthritis. It is due to inflammation and thickening of the synovium surrounding the dens and may lead to ligament laxity, and bone erosion resulting in C1-C2 joint laxity and subluxation with possible spinal cord compression. MRI is the imaging modality of choice to assess ROP and evaluate its extent. Three patterns of ROP are described following histological features; distinguish inflammatory hyper vascular pannus (hyperintense on T2-weighted images and enhancing) (Figure 1 and 2), combined pannus (intermediate signal intensity on T2- weighted images and intermediately enhancing), and fibrous pannus (low signal intensity on all sequences and non-enhancing).

Correlation between surgical findings and magnetic resonance imaging of deep infiltrating endometriosis

In this review, images during surgical excision of Deep Infiltrating Endometriosis (DIE) were correlated to preoperative Magnetic Resonance Imaging (MRI) findings. MRI is known to be the best tool for mapping DIE, it displays a high accuracy in the diagnosis and the characterization of endometriosis lesions. Recent studies showed also that MRI findings can be correlated to the length of operating time, to the duration of hospital stay, and to the risk of voiding problems. In this article we emphasize on the importance of having an experienced radiologist that has the ability of detecting adhesions and superficial peritoneal lesions, a value that was underestimated in previous studies. DIE presents on MRI as an intermediate signal intensity on T1-weighted images, hypointense signal on T2-weighted images, and homo- or heterogeneous enhancement after intravenous gadolinium injection. Preoperative MRI findings help doctors to elaborate a tailored therapeutic plan for each patient depending on the clinical context (Fertility preservation, IVF, complete surgical excisions). Most importantly correct investigation and accurate description of small lesions enhance surgical planification and adequate information of the patients.

Magnetic resonance imaging of the normal dromedary camel tarsus

Background: Magnetic resonance imaging (MRI) is the most versatile and informative imaging modality for the diagnosis of locomotor injuries in many animal species; however, veterinary literature describing the MRI of the dromedary camel tarsus is lacking. Our purpose was to describe and compare the MRI images of twelve cadaveric tarsi, examined in a 1.5 Tesla MRI scanner, with their corresponding anatomical gross sections. Turbo spin-echo (TSE) T1-weighted (T1), T2-weighted (T2), proton density-weighted (PD), and short tau inversion recovery (STIR) sequences were obtained in 3 planes. Tarsi were sectioned in sagittal, dorsal, and transverse planes. MRI images from different sequences and planes were described and compared with the anatomical sections.Results: The soft and osseous tissues of the dromedary camel tarsus corresponded extensively with the gross anatomic sections. T1 and PD images provided high anatomical details and the synovial fluid had high signal intensity on T2, PD, and STIR sequences and intermediate signal intensity on T1 images. The tibial cochlea, tarsal bones, and the proximal metatarsus were evaluated in all planes. The sagittal and dorsal images were useful for the evaluation of articular cartilage and subchondral bone. Articular cartilage had homogenous intermediate signal intensity on the T1 images and low signal intensity on the T2 and PD images. The Subchondral and cortical bone had low signal intensity on all sequences, and the cancellous bone expressed heterogeneous signal intensity on PD, T1, and T2 images. The tarsal tendons and ligaments had low signal intensity in all sequences including: the tendons of fibularis tertius, long digital extensor, cranial tibial, fibularis longus, lateral digital extensor muscles; the common tendon of the caudal tibial and lateral digital flexor muscles; the medial digital flexor tendon; the long and short bundles of the medial and lateral collateral ligaments; the superficial and deep digital flexor tendons; and the long plantar ligament. Conclusions: MRI images provided a thorough evaluation of the normal dromedary camel tarsus. Information provided in the current study is expected to serve as a basis for interpretation in clinical situations.

Polyorquidism: case report comparing ultrasonography and magnetic resonance imaging

Introduction: polyorchidism is an unusual pathology, about 200 cases in the world literature. Case report: we reported a case of polyorchidism in a 16-year-old male patient diagnosed by ultrasound and confirmed by magnetic resonance imaging. Discussion: most of the cases presented, there is a supernumerary testis, but there are reports on more than three, up to five testicles with supranumerical gonads on both sides of the scrotum. The diagnosis is usually performed in late puberty, incidentally, with a painless scrotal mass or at the emergency room, presenting a testicular torsion of the whole hemiscrotum or supernumerary testisalone, and the differential diagnosis should be made with epididymal cyst and spermatocele, besides other extra-testicular masses (hydroceles, varicoceles, lipomas, tumors.) and para-testicular masses (hernias, scrotal calculi). After the initial clinical evaluation, ultrasound is the first line subsidiary exam. Magnetic Resonance Imaging is very helpful, just in case the ultrasound diagnosis is uncertain. The supernumerary testishave the same Magnetic Resonance Imaging characteristics as the normal testes (intermediate signal intensity on T1- weighted images and high signal intensity on T2-weighted images).

MRI Features of Presumed Primary Extranodal Lymphoma of the Bulbospongiosus Muscle Causing Stranguria

ABSTRACT Hematopoietic neoplasia is common in dogs, with canine non-Hodgkin lymphomas representing more than 80% of all hematopoietic cancer. However, extranodal infiltration of the skeletal muscle by non-Hodgkin lymphoma is rare in humans and dogs. A 9 yr old neutered male English mastiff presented with a 3 wk history of recurrent stranguria, pelvic limb ataxia, and mild proprioceptive deficits bilaterally, worse in the right pelvic limb. MRI showed an expansile ill-defined lesion within the bulbospongiosus muscle. The lesion had intermediate signal intensity to muscle and fat on T2-weighted imaging and was isointense to unaffected muscle on precontrast T1-weighted imaging. Contrast enhancement was heterogeneous and there was digitate signal alteration within adjacent perilesional fat. Ultrasound examination confirmed a hypoechoic lesion infiltrating the muscle. Cytological examination yielded a diagnosis of high-grade lymphoma. This report provides the first description of MRI findings associated with cytologically confirmed lymphoma of the skeletal muscle in the dog. Although nonspecific, the imaging features strongly correlate with those in the medical literature and lymphoma should be considered a pertinent differential in cases presenting with similar imaging findings.

Magnetic resonance imaging of the normal dromedary camel tarsus

Background The role of magnetic resonance imaging (MRI) in veterinary practice continues to grow. MRI is currently the most versatile and informative imaging modality for diagnosis of soft tissue injuries in many animal species; however, veterinary literature describing the MRI of the dromedary camel tarsus is lacking. Our purpose was to describe and compare the MRI images of twelve cadaveric tarsi, examined in 1.5 T MRI scanner, with their corresponding anatomical gross sections. Turbo spin-echo (TSE) T1-weighted (T1), T2-weighted (T2), proton density-weighted (PD) and short tau inversion recovery (STIR) sequences were obtained in 3 planes. Tarsi were sectioned into sagittal, dorsal and transverse planes. Relevant osseous and soft tissue structures on MRI images and corresponding cryosections were identified and labeled. Results The overall quality of MRI images was adequate and informative. The soft and osseous tissues of the dromedary camel tarsus corresponded well with the gross anatomic sections. The sagittal and dorsal images were the most valuable for evaluation of articular cartilage and subchondral bone. T1 and PD sequences provided high anatomical details. T2 and STIR images were valuable for evaluation of synovial fluid. Articular cartilage had homogenous intermediate signal intensity. Subchondral and cortical bone had low signal intensity and cancellous bone had heterogeneous signal intensity. Tendons and ligaments had low signal intensity. Synovial fluid had high signal intensity on T2, PD and STIR sequences and intermediate signal intensity on T1 images. Conclusions MRI images provided a thorough evaluation of the normal dromedary camel tarsus. Information provided in the current study is anticipated to serve as a basis for interpretation in clinical situations.

Radiological diagnostic features of uremic leontiasis ossea: a case report

Uremic leontiasis ossea (ULO), which occurs in the craniomaxillofacial region, is a sign of terminal stage osteitis fibrosa cystica or brown tumors and primarily caused by secondary hyperparathyroidism induced by renal failure. Pathophysiological changes include osteoclasts or osteoblasts proliferation, bone resorption, bone decalcification, and connective tissue proliferation. In this paper, we report a case of a 24-year-old female patient, who was diagnosed with ULO and presented with multiple facial swellings. Imaging features included zonal patterns with alternating rings of hypo- and hyperattenuated craniomaxillofacial bones, and diffused mixed sclerotic tissues with lytic changes in CT imaging. T1 weighted image and T2 weighted image in MRI were characterized by alternating rings of low and intermediate signal intensity patterns. To the best of our knowledge, this case is the first example of pathologically proved ULO with maxillofacial MRI.

Retroperitoneal Liposarcoma with Multilocular Cysts

In this study, we describe a 60-year-old man with a giant retroperitoneal liposarcoma with multilocular cysts. He was admitted to our hospital because of a 5-month history of abdominal distention. Abdominal computed tomography revealed a giant lobulated cystic mass occupying the retroperitoneal space that contained partially solid fat components. Magnetic resonance imaging indicated that this complex mass exhibited a low signal intensity on a T1-weighted image, whereas it exhibited a high and focally intermediate signal intensity on a T2-weighted image. This patient was diagnosed with a mucinous type of retroperitoneal sarcoma, which was then resected. During surgery, the tumor was isolated from the retroperitoneum and other organs, but the detachment was required only because of fixation around the left external iliac artery. The histological diagnosis was a well-differentiated liposarcoma with multilocular cysts that contained old bloody, serous, and mucinous fluids, which are a rare phenomenon in liposarcoma. This case indicates that retroperitoneal liposarcoma should also be considered as a differential diagnosis of retroperitoneal cystic mass.

Diagnostic value of magnetic resonance imaging in the analysis of ameloblastoma: report of two cases

Ameloblastoma is an odontogenic tumor that shares clinical and imaging characteristics with other lesions of the jaws, such as odontogenic keratocyst, which makes the diagnosis difficult. However, in addition to radiographic and tomographic examinations, Magnetic Resonance Imaging (MRI) has been increasingly used, contributing with relevant additional information about the differentiation between solid and liquid components of the lesion. This case report was conducted to present two variations of ameloblastoma and discuss the radiographic, tomographic and MRI contribution in the differential diagnosis between ameloblastoma and odontogenic keratocyst.The signal intensity in T1-weighted MRI revealed internal fluid content in both cases, which was important in the differential diagnosis with other intraosseous lesions such as odontogenic keratocysts. This is probably due to the presence of keratin that increases the viscosity of the content and also for an intermediate signal intensity signal in T2-weighted MRI. Therefore, MRI revealed important internal characteristics of the reported lesions, which was very useful in the establishment of the differential diagnosis with other lesions.