UNASSIGNED: Metallosis which is traditionally associated with Metal-on-Metal (MoM) hip arthroplasty can occur with other bearing surfaces too, posing diagnostic challenges. They can be asymptomatic or present with local and systemic symptoms. This article reports a case of metallosis in a total hip replacement (THR) with metal on polyethylene (PE) articulation who presented with dislocation. It also reviews the pathology and various presentations of metallosis following hip arthroplasty.
UNASSIGNED: A 35-year-old female patient presented 4 years after a left THR with recurrent dislocation. It was an uncemented prosthesis with metal on PE articulation. Serology and radiological investigations were done to evaluate for infection, implant loosening, implant malposition, etc. The femoral stem appeared to be in varus malposition. She was posted for revision surgery with a pre-operative plan to change the femoral stem and head if necessary. Intraoperative signs of local metallosis were noticed. Debridement was done along with the change of the femoral stem and bearing surface to ceramic on PE. Metallosis was also later confirmed by the histopathological report. The patient has been symptom-free during the 2-year follow-up period.
UNASSIGNED: Metallosis can occur even in non-MoM articulations and a high degree of clinical suspicion is required to detect the same preoperatively. Classical signs of metallosis can often be absent in the early disease and subtle signs of instability must be looked out for even in the absence of obvious misalignment in radiographic assessment. Metallosis when combined with malposition or malalignment can be more detrimental. If detected early before osteolysis and periarticular soft tissue damage sets in, a complete revision of all the implant components and abductor damage can be avoided. In suspected cases, a lower threshold should be adopted for sending blood and joint aspirates for cobalt-chromium levels.

OBJECTIVE: Hemophilic pseudotumor (HP) is a very rare complication of hemophilia seen in only 1-2% of the cases. Although it is much more common in long bones, pelvis and small bones of hands and feet and very rarely involving jaw bones.
RESULTS: In the present case, the presence of a rare hemophilic pseudotumor of the mandible with the positive history of Hemophilia B justifies that the history, clinical and radiological examinations were sufficient to arrive at conclusive diagnosis precluding invasive diagnostic procedures such as biopsy hence avoiding the risk of hemorrhage, infection, or fistula. This case also highlights that patient was conservatively managed with Factor IX replacement alone with a very good clinical outcome.
CONCLUSIONS: HP should be considered as a differential diagnosis of any progressive swelling of hard and soft tissues occurring in a patient with severe haemophilia.

UNASSIGNED: Fibromatosis colli (FC) is a rare pseudotumor of the sternocleidomastoid muscle with an incidence of 0.4%, generally diagnosed using ultrasound between 2 and 4 weeks of age. This is an important entity considering the clinical concerns it causes due to its appearance as a cervical mass with torticollis. Few magnetic resonance imaging (MRI) descriptions of its appearance have been made, with the existing reported cases being sporadic. We aim to provide a thorough description of this paediatric entity.
UNASSIGNED: We conducted a retrospective study by searching our hospital\'s database for previous cases of FC where an MRI had been performed. We found six cases of FC where an MRI had been performed. Of these cases, five out of six were contrast-enhanced. We examined the MRIs to be able to discern and describe the MRI characteristics of FC.
UNASSIGNED: We found that FC presents a T1 signal isointense to the muscle, a T2 signal hyperintense to the muscle, a variable diffusion signal and a thick enhancing peripheral ring after contrast administration.
UNASSIGNED: Our results match what has been reported in the literature to date regarding the MRI signal of FC, confirming previous reports. However, we provide new data regarding the characteristic appearance post-enhancement, which was previously unreported.
UNASSIGNED: The MRI characteristics of FC have rarely been described, with only a few isolated case reports in the medical literature. We review the current literature, describe the key MRI characteristics of the pathology, and provide the most thorough description to date.

Arthroplasty-related pseudotumors are nonneoplastic and noninfectious inflammatory masses that are typically associated with adverse reaction to metal debris. Pseudotumors most commonly occur in the setting of metal-on-metal joint replacements at the hip. However, the presentation of pseudotumor at the shoulder is exceedingly rare. In this article, we reported a case of arthroplasty-related pseudotumor of the scapula. Clinical history, radiologic signs, and tissue analysis are described. Knowledge of this rare diagnosis will support clinical decision making for teams of radiologists, pathologists, oncologists, and orthopaedic surgeons who provide care for patients presenting with suspicious shoulder masses.

Hemophilic pseudotumor is a rare, yet dangerous complication of hemophilia. It has been reported previously at sites prone to recurrent trauma like long bones and pelvis. However, in the field of otorhinolaryngology, few cases are reported and therefore there is no established protocol for management. We hereby report a case of a 2-year-old boy, a known case of hemophilia A (factor VIII deficiency), who presented with recurrent epistaxis not responding to medical management. Imaging was done and revealed a heterogenous nasal mass compressing the left orbital wall, extending to the sphenoid sinus, and causing skull base erosion. The patient was successfully managed by evacuation and drainage of the pseudotumor via endoscopic endonasal approach and replacement of factor VII pre-and post-operatively. To our knowledge, this is the first case of nasal hemophilic pseudotumor managed by evacuation and drainage through an endoscopic endonasal approach, which was deemed successful.

Total hip arthroplasty (THA) is a common treatment for osteoarthritis and is also performed for other conditions, such as secondary arthritis due to developmental dysplasia of the hip. Various THA types may be complicated by osteolysis and an inflammatory pseudotumor due to an adverse reaction to metal debris. Rarely, THA has been associated with malignant tumors, but their causality remains unclear. In this case report, we describe a female patient with developmental dysplasia of the hip. She had undergone left metal-on-polyethylene THA, acetabular revision of the THA, and left total knee arthroplasty. In addition, she had a history of dyslipidemia and telangiectasia of the eyes, anemia, hiatal hernia, and pleuritis. A THA-associated mass (suspected to be a pseudotumor) had been detected during a previous hospital admission due to pleuritis. She was hospitalized due to swelling in her left lower limb, fatigue, and bruises. A clinical examination revealed anemia, thrombocytopenia, and growth of the suspected pseudotumor. Within 6 weeks, she presented with bleeding of the oral mucosa, hemoptysis, melena, severe thrombocytopenia that did not respond to treatment, elevated D-dimer and C-reactive protein levels, severe pain, increased osteolysis, and fractures around the THA. Infection or malignancy was suspected, but two trocar biopsies suggested an inflammatory pseudotumor. Since her anemia and thrombocytopenia were considered to have been caused by an inflammatory process within the suspected pseudotumor, her suspected pseudotumor and all THA components were surgically removed. However, she developed severe alveolar hemorrhaging and hypoxia and died 2 weeks after her surgery. Histopathological analysis of her surgical and autopsy samples revealed highly malignant angiosarcoma. Although individual cases of malignancies associated with THA have been reported, the literature lacks a clear association between THA and increased cancer risk. Most pseudotumors are non-malignant. The patient\'s case presented in this report exemplifies the challenges to the differential diagnosis of a THA-associated pseudotumor and rare angiosarcoma. Atypically rapid tumor growth, severe osteolysis, and deterioration in the general wellbeing suggest a malignant disease.

Immunoglobulin G4-related disease (IgG4-RD) is an autoimmune-mediated disorder with heterogeneous multiorgan manifestations. Early identification and treatment of IgG4-RD are crucial for organ function recovery. Rarely, IgG4-RD manifests as a unilateral renal pelvic soft tissue mass that may be misdiagnosed as urothelial malignancy, resulting in invasive surgical intervention and organ damage. Here we present a 73-year-old man who had a right ureteropelvic mass with hydronephrosis detected by enhanced computed tomography. Right upper tract urothelial carcinoma and lymph node metastasis was highly suggested based on the image findings. However, IgG4-RD was suspected due to his past history of bilateral submandibular lymphadenopathy, nasolacrimal duct obstruction, as well as a high serum IgG4 level of 861 mg/dL. The ureteroscopy with tissue biopsy showed no evidence of urothelial malignancy. His lesions and symptoms improved after glucocorticoid treatment. Hence, a diagnosis of IgG4-RD was made, with the phenotype of classic Mikulicz syndrome with systemic involvement. The manifestation of IgG4-RD as a unilateral renal pelvic mass is rare and should be kept in mind. A ureteroscopic biopsy and serum IgG4 level measurement can help in the diagnosis of IgG4-RD in patients with a unilateral renal pelvic lesion.

UNASSIGNED: Paratesticular fibrous pseudotumor (PFP) is a rare intrascrotal benign fibrous mass of uncertain aetiology, usually arising between testicular tunica layers and is supposed to be related to inflammatory reactive conditions. Because of morphological similarities to IgG4-related sclerosing fibro-inflammatory lesions, some authors recently postulated that PFP might belong to the IgG4-related disease (IgG4-RD) family. Considering the rarity of this lesion, only few cases have been reported in literature about the correlation between IgG4-RD and PFP. Management of PFP could be extremely challenging: due to the lack of typical clinical signs and the non-specific radiological characteristics, misapprehension does occur in the majority of cases, mainly because these intrascrotal mass may mimic testicular neoplasm, therefore leading to radical orchidectomy rather than a desirable testis-sparing surgery.
UNASSIGNED: Herein we report two cases of young males treated for PFP with histological feature of IgG4-RD. Patients underwent testicular sparing surgery. At 2-year follow-up no evidence of local or distant relapse nor testicular disorder was observed in both patients. An up-to-date review of the literature about the correlation between PFP and the IgG4-RD was carried out.
UNASSIGNED: PFP is an extremely rare condition with uncertain etiology being part of IgG4-RD family. Preoperative imaging mimics malignancy hence diagnosis is usually made by specimen analysis. Intraoperative frozen section is fundamental in order to guarantee conservative treatment that is feasible and safe after mid-term follow-up.

Inflammatory myofibroblastic tumor (IMT) is a rare type of tumor composed mainly of fibroblastic and myofibroblastic spindle cells, with an inflammatory infiltrate of lymphocytes, plasma cells, and eosinophils. IMT may arise from different organs and sites, but it is infrequent to arise from the urinary bladder and usually manifests as hematuria. We report a case of a 24-year-old pregnant woman who presented to our hospital with gross hematuria. After further workup, we concluded that she had this extremely rare tumor, which was resected eventually with a partial cystectomy. Although the diagnosis of these kinds of tumors is usually made by anaplastic lymphoma kinase (ALK) using immunohistochemistry and detecting ALK gene translocation using fluorescence in situ hybridization (FISH), they were negative in our study; hence, we relied mainly on the morphological features of the tumor for the diagnosis.

Cytomegalovirus (CMV) oophoritis is an extremely rare and fatal condition. We encountered a 63-year-old woman with CMV oophoritis who had been treated for Burkitt\'s lymphoma. Positron emission tomography/computed tomography performed after chemotherapy showed a high 18F-fluoro-2deoxy-D-glucose uptake in both ovaries, which required distinguishing relapse. CMV oophoritis was diagnosed on histology following bilateral salpingo-oophorectomy. Although the patient later developed recurrent episodes of CMV antigenemia, after which complications of CMV retinitis appeared, and she ultimately died of CMV meningitis, surgical resection with antiviral medication resolved her abdominal symptoms and cleared CMV antigenemia for several weeks. It is therefore worth considering surgical resection in combination with antiviral drugs as a treatment option.