Inflammatory pseudotumor, the great mimicker: A case report

Inflammatory pseudotumor is a rare lesion, especially at the level of the central nervous system. Its etiology is unknown and the most accepted hypothesis is that it is the consequence of an exaggerated immune response. We present the clinical case of a young Senegalese male, with a history of epilepsy secondary to severe cranioencephalic trauma in childhood, who presented with new epileptic seizures. Imaging tests showed a lesion in the anterior fossa intimately attached to the meninges, so the initial diagnosis was meningioma. A bifrontal craniotomy and microsurgical excision were performed. The definitive anatomopathological analysis concluded that the lesion is an inflammatory pseudotumor whose origin is secondary to a disproportionate reparative process after cranioencephalic trauma.

Pseudotumor from ceramic-on-ceramic total hip arthroplasty

INTRODUCTION AND IMPORTANCE

Total hip arthroplasty is one of the most performed surgical interventions in the world. Adverse local tissue reactions and pseudotumors are infrequent but dangerous eventualities, which are often related with metal-on-metal or metal-on-polyethylene implants. This study wants to highlight how adverse local tissue reactions and pseudotumors must be taken into consideration during the diagnostic process.

CASE PRESENTATION

We report the case of a patient with ceramic-on-ceramic modular total hip arthroplasty with titanium neck. 12 years after surgery, he complained of pain and swelling on the hip. Diagnostic tests revealed the presence of a bulky pseudotumor. During the revision surgery biopsy samples were taken and microscopical analysis revealed the presence of fibrous tissue, fibrin hemorrhagic collections, histiocytes and chronic inflammation due to foreign body, with dark refractive material of an exogenous nature.

CLINICAL DISCUSSION

The possible formation of pseudotumor and metallosis reactions in hip prostheses with metal-on-metal coupling or in couplings with polyethylene is known. Many cases of pseudotumor are reported after revision of prostheses due to the breakage of ceramic components, but we did not observe any damage or corrosion of the prosthetic elements; on the other hand, we noticed an excessive retroversion of the femoral neck. It may be possible that an accurate microscopic analysis could clarify the failure of this implant.

CONCLUSION

To date ceramic-ceramic coupling remains the gold standard in terms of resistance and durability for hip arthroplasty but there is still a gap of knowledge in the field of tribology and individual immune response mechanisms.

Synchronous tumors of gastric carcinoma combined gallbladder cancer and pseudotumor chronic pancreatitis

INTRODUCTION AND IMPORTANCE

Synchronous primary cancers in the stomach and gallbladder were not previously reported in the medical literature. Pseudotumor pancreatitis was also described many years ago. It was misdiagnosed and required surgery for pancreatic head neoplasms.

PRESENTATION OF CASE

A 57-year-old male patient went to our hospital for abdominal pain. He was indicated for gastroduodenal endoscopy, and the result was adenocarcinoma. Abdominal ultrasound and Ctscan detected the gallbladder fundus's localized thickening structure and the pancreatic head's hyperechoic structure. The endoscopic ultrasound and MRI showed a gallbladder + pancreatic head tumor with chronic pancreatitis with pancreatic stones. The patient underwent distal gastrectomy, cholecystectomy, and pancreaticoduodenectomy.

CLINICAL DISCUSSION

The detection of gastric cancer is often based on upper gastrointestinal endoscopy and biopsy results. Gallbladder cancer is often diagnosed at an advanced stage, and only very few patients are diagnosed early. Pancreatic cancer often occurs in the head of the pancreas. Symptoms may include obstruction of the common bile and Wirsung duct, often in advanced stages. Surgery for the gallbladder, distal stomach, and head of pancreatic tumors are related to each other located in a neighboring location in the anatomy, so surgery to remove all three tumors is relatively similar to a pancreaticoduodenectomy procedure.

CONCLUSION

Synchronous tumors of gastric carcinoma combined with gallbladder cancer and pseudotumor chronic pancreatitis are rare. The attitude of treating these three diseases at the same time requires a tumor board. Simultaneous surgery for gallbladder, stomach, and pancreatic head tumors can be performed if the tumors are still in the resectable stage.

Histopathologic clues to the etiopathogenesis of orbital inflammatory disease: Idiopathic, IgG4-related, neoplastic, autoimmune and beyond

Orbital inflammatory diseases represent a heterogenous group of idiopathic, autoimmune-related, and sometimes neoplastic conditions with overlapping clinical and histopathologic features, as well as variable levels of IgG4-positive plasma cells detected within tissue biopsies. Some histopathologic features, especially in an appropriate clinical context, may point to a specific diagnosis in a given patient. Diagnoses of non-specific orbital inflammation, orbital inflammation related to autoimmune diseases such as granulomatosis with polyangiitis and IgG4-related disease, lymphoma, and xanthogranulomatous diseases are discussed, contrasted and illustrated.

A subgroup analyses of a randomized controlled trial

BACKGROUND

Pseudotumors and muscle atrophy have been associated with metal-on-metal (MoM) resurfacing hip arthroplasty (RHA). We aimed to investigate the influence of the anterolateral (AntLat) and the posterior (Post) surgical approach on the location, grade and prevalence of pseudotumors and muscle atrophy in MoM RHA.

PATIENTS AND METHODS

Forty-nine patients were randomized to MoM RHA by the AntLat (n = 25) or the Post (n = 24) approach at Aarhus University Hospital. Patients underwent metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) scans for investigation of location, grade and prevalence of pseudotumors and muscle atrophy. Plain radiographs, metal-ions concentrations and clinical outcome scores were evaluated to compare outcomes of the surgical approaches.

RESULTS

MRI-detected pseudotumors were seen in 7 of 18 patients (39%) in the AntLat group and in 12 of 22 patients (55%) in the Post group (p = 0.33). Pseudotumors were mainly located anterolaterally to the hip joint in the AntLat group and postero-lateral to the hip joint in the Post group. Higher grades of muscle atrophy of the caudal part of the gluteus medius and minimus (p < 0.004) were seen in the AntLat group, and higher grades of muscle atrophy of the small external rotators were seen in the Post group (p < 0.001). The AntLat group had higher anteversion angles of mean 15.3° (range 6.1-7.5) versus mean 11.5° (range 4.9-22.5) in the Post group (p = 0.02). Metal-ion concentrations and clinical outcome scores were similar between groups (p > 0.08).

CONCLUSION

Muscle atrophy and pseudotumor location after MoM RHA follow the surgical approach used for implantation. This knowledge may help differentiate between "normal postoperative appearance" and "MoM disease."

Metallosis and Corrosion Associated With Revision Total Knee Arthroplasties With Metaphyseal Sleeves

Metallosis and corrosion have been associated with metal-on-metal and modular total hip arthroplasty but are rarely described in the setting of primary or revision total knee arthroplasty (TKA). In this series, we report on cases of metallosis due to mechanically assisted crevice corrosion at modular junctions of machined trunnion-bore tapers in a revision TKA system with metaphyseal sleeves. The unique design of metal modular junctions used in sleeve-based revision TKA, along with potential patient and surgical factors, may predispose these designs to fretting, corrosion, and adverse reaction to metal debris. We now consider metallosis and corrosion in the workup of painful or failed revision TKAs with sleeves. Future studies that investigate the incidence of this phenomenon may be warranted.

Do polyethylene wear particles affect the development of pseudotumor in total hip arthroplasty? A minimum 15-year follow-up

BACKGROUND

Adverse local tissue reactions have been problematic as an implant-related complication in total hip arthroplasty (THA). Despite the absence of significant metal wear and corrosion, granulomatous pseudotumor has been reported to be caused by polyethylene wear. We performed a long-term follow-up study investigating the relationship between polyethylene wear and pseudotumor formation in THA.

METHODS

This study included 57 patients (64 hips) that underwent primary THA with metal-on-polyethylene or ceramic-on-polyethylene bearing over a minimum follow-up of 15 years. They were stratified into pseudotumor and non-pseudotumor groups and their linear wear rates of polyethylene liner and serum cobalt (Co) and chromium (Cr) ion levels were compared. Pseudotumor was diagnosed on metal artifact reduction sequence-MRI according to its composition and wall thickness using the Hauptfleisch classification.

RESULTS

The incidence of pseudotumor was 34% (22/64 hips) at the mean follow-up of 16.9 years. Metal ion levels did not differ between the pseudotumor and non-pseudotumor groups, and none of the patients exceeded the Co/Cr ratio of 2.0 μg/L. Moreover, the wear rate in the pseudotumor group was 1.8 times greater than in the non-pseudotumor group (0.14 vs. 0.08 mm/year, P < 0.001). According to an analysis of the receiver operating characteristic curves, the cutoff level of the wear rate to discriminate between pseudotumor and non-pseudotumor patients at 15 years was 0.11 mm/year (area under the curve = 91%; sensitivity = 95%; specificity = 78%; accuracy = 87%).

CONCLUSIONS

Our results might provide new insights into excessive polyethylene wear potentially leading to the future development of both pseudotumor and osteolysis. Further studies are needed to clarify the direct relationship between polyethylene wear and pseudotumor and the mutual effects of osteolysis and pseudotumor in particle reactions.

Uterine inflammatory myofibroblastic tumor

Inflammatory myofibroblastic tumor (IMT) is recognized as a true neoplasm of unknown etiology, but its pathogenesis is related to abnormalities in the ALK gene. This is an uncommon tumor with a wide anatomic distribution and often constitutes a challenging diagnosis owing to its histological similarities with other tumors. Uterine IMTs are rare and their detailed characteristics should be described based on case reports and small case series. Thus, we performed a comprehensive review of the literature showing that uterine IMTs show a wide range of age at diagnosis (median, 39 years), and a symptomatology similar to that of common leiomyomas, only rarely presenting with inflammatory manifestations. IMTs represent 0.1% of "leiomyomas," an estimate that increases to 10% for pregnant women and to 14% for the smooth muscle tumors of uncertain malignant potential (STUMP) category of tumors, implying that tumors excised during pregnancy, STUMPs, and leiomyosarcomas should be systematically screened with ALK immunohistochemistry, as this is a targetable abnormality. Most reported cases are ALK-positive; the fusion partners vary, but in pregnancy-associated tumors, TIMP3 prevails. Almost 25% of the patients will show an aggressive course, and this is associated with older age, non-pregnancy-associated tumors, larger tumors, infiltrative tumor border, absence of abundant inflammation, atypia, important mitotic activity, and necrosis.

Adverse reaction to metal debris with accompanying gout and amyloid deposits in hip arthroplasty

Adverse reaction to metal debris (ARMD) is a known complication of metal-on-metal hip arthroplasty. There has been one previously reported case of ARMD with concomitant gout in the setting of a hip arthroplasty. We report a case of ARMD with accompanying monosodium urate crystals as well as amyloid deposition in the hip of a patient who had undergone a metal-on-metal hip arthroplasty. This is the only published case to date of these 3 conditions co-existing, although it is possible that the incidence is higher since these require special diagnostic tests that are not routinely performed. It is postulated that these entities are biochemically associated with each other rather than being purely coincidental.

Epididymal bilharzia simulating a testicular tumor: A case report

Bilharzia or schistosomiasis is a parasitic disease due to infestation by a hematophagous trematode of the genus Schistosoma. It is the second most frequent parasitic endemic in the world after malaria. The most frequent tissue infections are intestinal and genitourinary. Testicular localizations of schistosoma are very rare. When lesions become chronic, they present as non-specific masses, bilharziomas, posing enormous problems of differential diagnosis with other benign and malignant pathologies, which impacts management. We report a case of epididymal schistosomiasis in a 37 years old patient simulating a malignant tumor. This case allowed us to review the diagnostic difficulties of this rare localization and the challenges of management.

Massive pseudotumor of unknown etiology in a cemented metal-on-polyethylene total hip arthroplasty: a case report

Background

The formation of destructive pseudotumors is a well-documented, albeit rare, complication of total hip arthroplasties. They tend to be progressive and, if left untreated, can result in extensive periprosthetic bony destruction. The current case presents a large benign mass consistent with a pseudotumor on both imaging and intraoperative findings but histologic findings demonstrating chronic hematoma.

Case Description

An 86-year-old female with a metal-on-polyethylene total hip presented with a massive pseudotumor accompanied by extensive bony lysis. Due to pain and chronic anemia, a palliative debulking procedure was undertaken as a palliative measure. At one year follow-up, the patient reported significant pain relief and was able to ambulate safely with gait aids. Her hemoglobin stabilized post-operatively and ongoing transfusions were not required. Final pathology was not supportive of particle disease despite this being the leading diagnosis. Microscopic sections showed tissue mostly composed of fibrin and blood with multiple foci of calcification and reactive papillary endothelial hyperplasia which can be seen in chronic hematomas.

Conclusions

This case presents the diagnostic dilemma of a large benign mass consistent with a pseudotumor on both imaging and intraoperative findings but histologic findings consistent with a chronic hematoma. It highlights the importance of close follow-up and early intervention when periprosthetic osteolysis is detected.

Adverse Local Tissue Reaction Associated With Ceramic-On-Metal Bearing Surface in Primary Total Hip Arthroplasty: Report of Two Cases

Total hip arthroplasty (THA) is one of the most common and successful surgical procedures worldwide. At the same time, it is constantly evolving, and as a consequence, advances in implant technology have led to significant improvements in the different materials of the acetabular and femoral components. The selection of bearing surfaces and their tribology are critical to achieving a successful outcome. Pseudotumors are important, and usually misdiagnosed, complications associated with hard bearing surfaces such as metal-on-metal couples. They belong to a group of reactions called adverse local tissue reaction, which can occur in the vicinity of any THA. We present 2 cases of adverse local tissue reaction associated with the use of ceramic-on-metal bearings surfaces in 2 primary THAs that were treated with modular component exchange during single-stage revision surgery.

Level of Evidence

IV.

Operative Technique for Resection of a Ventral Trans-Dural Retro-Odontoid Pannus: A 2-Dimensional Operative Video

Retro-odontoid pseudotumors are rare inflammatory complications of atlantoaxial instability often associated with cervical degenerative disease and rheumatoid arthritis. While propagation of these lesions has been shown to cause spinal cord compression and cervical myelopathy, intradural extension has rarely been reported. In this manuscript and two-dimensional illustrative intra-operative video, we demonstrate cervical decompression, removal of the intradural component, and stabilization with C1-2 instrumentation utilizing a posterior approach. A 71 year old patient presented with progressive cervical myelopathy. Preoperative imaging demonstrated a large retro-odontoid pannus causing severe spinal cord compression and an associated contrast-enhancing intradural lesion, in the absence of obvious C1-2 instability or fractures on CT scan. C1-2 posterior decompression and fusion were performed with maximally safe intradural pannus resection and ventral dural reconstruction. Postoperatively, the patient experienced significant improvement in myelopathic symptoms. Imaging demonstrated good spinal cord decompression with complete intradural pannus resection and debulking of the extradural component. Our outcome in this rare complication suggests a posterior approach may be effective in treating similar patients.

Metallosis following hip arthroplasty: two case reports

Background

There has been increasing recognition of local and systemic adverse events associated with the release of metal ions and nanoparticles from hip arthroplasty components. Adverse local tissue reactions to metal ion debris can include periprosthetic solid and cystic masses known as pseudotumors. These masses can result in pain, swelling, extensive destruction to surrounding hip soft-tissues, and compression syndromes on neurovascular, gastrointestinal, and genitourinary structures. As reports of pseudotumors requiring multidisciplinary excision are limited, we present two pseudotumor cases that were excised through a combined approach.

Case presentations

The first case involves a 60-year-old Caucasian female with a large pseudotumor with intrapelvic and vascular involvement associated with a metal-on-polyethylene total hip arthroplasty, excised with contributions from general surgery, vascular surgery, and orthopedic surgery. Pseudotumor excision was followed by a revision total hip reconstruction in addition to an abductor mechanism reconstruction with tendo-Achilles allograft. The second case is that of a 64-year-old Caucasian female with a pseudotumor in close relationship to the femoral vessels following a metal-on-metal hip resurfacing, excised with a combination of vascular surgery and orthopedic surgery, with subsequent revision total hip reconstruction.

Conclusions

There remains a lack of literature to support the extensiveness of pseudotumor excision required in complex cases with significant intrapelvic or vascular involvement. Given the potential for significant adverse effects of large masses, the authors’ preference is to involve a multidisciplinary team to achieve a more comprehensive excision while minimizing the risk of potential complications.

Myositis ossificans: a rare neonatal presentation

Myositis ossificans is a benign, ossifying, soft-tissue pseudotumor that most commonly occurs in men ages 30-40 years after trauma. Myositis ossificans may also occur in children, but it is extremely rare in those younger than 10 years of age. While myositis ossificans can often mimic malignant soft-tissue tumors, it has many unique findings that can aid in diagnostic differentiation. This differentiation is critical to avoid unnecessary risk with potentially harmful procedures. We present a very unusual presentation of myositis ossificans in the immediate post-birth perinatal period, as well as a review of key imaging findings.

Fibromatosis Colli: A case report

Fibromatosis Colli also known as congenital torticollis is a rare cause of benign cervical pseudotumor in neonates, consisting of benign fibrous tissue proliferation within the sternocleidomastoid muscle, resulting in a fusiform enlargement. The cause of fibrosis is unknown; however it could be linked to trauma during pregnancy or at the time of birth, resulting in hemorrhage and, subsequently, fibrosis. Ultrasound plays a necessary role in confirming this diagnosis and follow-up. We Report a case of Fibromatosis colli in a four-week old newborn who was diagnosed using ultrasonography and treated with physiotherapy.

Current clinical and therapeutic approach to tumour-like mass lesions in granulomatosis with polyangiitis

Granulomatosis with polyangiitis (GPA) is a systemic autoimmune disorder classified among the anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and characterized by a triad of upper and lower respiratory tract disease, systemic vasculitis involving small-to-medium vessels and renal manifestations. Mass lesions, also described as inflammatory lesions, pseudotumor or tumour-like masses, are uncommon manifestations of GPA and are often called granuloma since histology examination shows granulomatous inflammation and rarely vasculitis. Masses could represent a localized manifestation of GPA or develop as part of a systemic disease. Unusual clinical presentation together with nonspecific radiological and histological features may delay the correct diagnosis leading to disease progression and organ damage. Diagnosis of GPA in such cases may be challenging and malignancy or infections must be considered as alternative diagnostic options. Here we reviewed all the different sites where mass lesions were reported in GPA, focusing on atypical localization, and summarized current therapeutic options and their different outcomes. We retrieved and discussed the cases reported since 2010, bearing in mind the advances in the therapeutic management of AAV patients in the last decade, namely biological therapy such as rituximab. Despite treatment regimens with glucocorticoids and immunosuppressive agents, mass lesions have a refractory course in a high proportion of patients. Invasive surgical procedures may be considered only when drug therapy fails.

Tigecycline sclerotherapy for recurrent pseudotumor in aseptic lymphocyte-dominant vasculitis-associated lesion after metal-on-metal total hip arthroplasty: A case report

BACKGROUND

Metal-on-metal (MoM) total hip arthroplasty (THA) has been associated with adverse reactions to metal debris, presenting clinically as pseudotumors.

CASE SUMMARY

This case report presents a female aged 73 year-old with MoM THA-related pseudotumor. After arthrotomy and bursectomy surgeries, histologic examinations of surgical specimens revealed a specific lymphocyte-dominant immunologic response, now known as aseptic lymphocyte-dominant vasculitis-associated lesion (ALVAL). Due to soft tissue persisting effusion after arthrotomy and bursectomy, revision surgery was then performed with ceramic-on-polyethylene THA. However, revision did not resolve the patient’s symptoms. Here we describe our application of tigecycline sclerotherapy to treat recurrent pseudotumor after revision THA and no recurrence after 24-mo follow-up.

CONCLUSION

Tigecycline sclerotherapy is safe and effective in the management of recurrent pseudotumor after revision non-MoM THA in ALVAL cases.

[Immunoglobulin G (IgG) 4-related diseases]

Immunoglobulin G (IgG) 4‑related diseases are fibrosing inflammatory systemic diseases that can affect almost every organ system. Typical disease manifestations include autoimmune pancreatitis, lymphadenopathy, retroperitoneal fibrosis, inflammatory orbitopathy and involvement of the salivary and lacrimal glands. Organ involvements can occur either isolated or in combination with other disease manifestations. Before diagnosing IgG4-related diseases, malignancies and other inflammatory diseases have to be excluded. The diagnosis requires a combination of laboratory findings, histological and radiological results. Typically, IgG4-related diseases respond well to glucocorticosteroids. In cases of relapse or severe organ involvement a longer term immunosuppression is often required, whereas watch and wait can also be sufficient in milder cases.

Tumors and pseudotumors of foot and ankle: Bone lesions

Bone tumors and tumor-like lesions (pseudotumors) are not uncommonly encountered as asymptomatic findings on imaging, or as symptomatic lesions clinically. Radiographic imaging is the first diagnostic tool for their management strategy, since the symptoms are commonly non-specific, such as pain, swelling, and redness. Image findings must be analyzed with attention to the specific features such as lesion location, margination, zone of transition, mineralization, size and multifocality, soft tissue component and/or loco-regional extent. Cross-sectional imaging including CT and MRI serve as complementary methods, providing additional information with respect to the lesion characterization, mineralization, extent and involvement of the adjoining soft tissues. Clinical and/or key imaging features aid in limiting the differential diagnostic possibilities and serve as a guide in determining the benignity or malignancy of the tumor as well as to exclude pseudotumors. This article reviews the key imaging features of foot and ankle lesions. Benign bone lesions include simple and aneurysmal bone cysts, lipoma, hemangioma, chondroblastoma, enchondroma, osteoid osteoma, osteoblastoma, and giant cell tumor. Locally aggressive intermediate category lesion includes hemangioendothelioma. Malignant lesions include osteosarcoma, Ewing's sarcoma, chondrosarcoma. Pseudotumors such as fibrous dysplasia, hemophilic pseudotumor, gout and Madura foot are also discussed with illustrative case examples.

Hypertrophy of the tensor fascia lata: A pseudotumor due to lumbar radiculopathy

Background

Pseudotumor of the tensor fascia lata (TFL) consists of a rare, benign soft tissue mass/hypertrophy of the TFL that appears on the anterolateral aspect of the proximal thigh. Notably, this condition often mimics a malignant tumor and may be misdiagnosed as a sarcoma.

Case Description

A 45-year-old male presented with left hip/groin pain, swelling, and a painful mass on the anterolateral aspect of the left hip/thigh. The symptoms had started 3 months ago following an L1-S1 lumbar laminectomy/fusion. The initial diagnosis was hip disease, and the patient underwent a left MR arthrogram. When this study demonstrated a tear of the left anterosuperior acetabular labrum plus an increased alpha angle causing femoroacetabular impingement, the patient then underwent a left hip arthroscopy. However, as he continued to complain of the hip mass, he was referred to an orthopedic oncologist whose presumptive diagnosis favored a sarcoma. Nevertheless, the pelvic MRI scan and ultrasound (US) confirmed the diagnosis of hypertrophy of the left TFL (US left 33.4 mm vs. right 14.4 mm). The patient was first treated with 50 units of locally injected botulinum. As there was no symptomatic relief, the plan was to repeat the injection within the next few months.

Conclusion

Hypertrophy of TFL may mimic a neoplasm such as a sarcoma and contributes to what appears to be a lumbar radiculopathy. However, MR and US imaging should readily identify TFL and rule out malignant lesions such as sarcomas.

Surgical management of hip prosthetic failure in metallosis: A case series and literature review

Local and remote complications can be observed in hip prosthesis failures associated with metallosis. Structural changes in the periprosthetic bone and soft tissues may not always be precisely assessed preoperatively due to metal artifacts. The unpredictability of the damage extension, potentially leading to complex and insidious surgeries, requires the availability of alternative surgical plan(s) for the reconstruction of the joint. The aim of the study is to present and analyze, with the literature data support, practical tips for the revision of the prosthetic components, the management of ARMD and of intraoperative complications in the unusual scenario of metallosis.

IgG4 related lung disease- a rare and novel mimic of malignancy and infections-a case series of three patients with a brief review of updated literature

IgG4-related lung disease is an extremely rare and novel entity which is still poorly understood. We reviewed the 16 patients diagnosed with IgG4-related disease from October 2014 through December 2019 at our institution. The three cases that showed pulmonary involvement are included in this series. Of these, two patients had cavitary lung disease and developed aspergilloma and chronic cavitating aspergillosis after a prolonged course of steroid therapy, and one had isolated pulmonary nodule and ground glass opacity. We reviewed the updated literature and briefly described disease epidemiology, clinical characteristics, diagnostic approaches, and management strategies for IgG4-related lung disease.

Imaging of orbital infectious and inflammatory disease in children

Most acute nontraumatic periorbital and intraorbital pathologies in pediatric patients have an underlying infectious or inflammatory etiology, and imaging frequently plays a key role in the workup and management of these children. In this paper we review the clinical presentation and imaging findings in children with some of the most common infectious and inflammatory diseases involving the orbit. Basic relevant anatomy and imaging findings on various imaging modalities are also reviewed.

Surgical treatment for patients with hemophilic pseudotumor-related femoral fracture: a retrospective study

BACKGROUND

Hemophilic pseudotumor (HPT)-related fracture is a rare but severe complication in patients with HPTs. These fractures often occur in femurs. There is no consensus on the standard surgical protocol for HPT-related femoral fracture. The present retrospective study evaluated the outcomes of these patients treated with surgical interventions.

METHODS

Ten patients with HPT-related femoral fractures who were treated with 14 surgical procedures due to 11 fractures in our hospital from January 2014 to April 2020 were evaluated retrospectively. Demographic data, fracture location, complications after surgery, and follow-up outcomes were recorded and analyzed. The mean follow-up period was 39.7 months.

RESULTS

The mean age at surgery was 31 years. Closed reduction external fixation (CREF) was originally performed in 2 patients, open reduction internal fixation (ORIF) was performed in 4 patients, screw fixation alone was performed in 1 patient, brace immobilization was performed in 1 patient, and amputation was performed in 3 patients. Bone union was observed in 5 patients, and an adequate callus was visible in 2 patients. Both patients with CREF had pin infections. Nonunion combined with external fixation (EF) failure occurred in 1 patient, and the plate was broken after ORIF. Three patients underwent autogenous or allogeneic cortical strut grafting. Three patients had HPT recurrence.

CONCLUSIONS

It is necessary to perform surgery in patients with HPT-related femoral fractures. Surgical treatments must consider fracture stabilization and HPT resection. Internal fixation is preferable, and EF should only be used for temporary fixation. If the HPT erodes more than one third of the bone diameter, strut grafts are necessary for mechanical stability. Amputation is an appropriate curative method in certain situations.

Fatal vascular complication due to metallosis

Metallosis is a well-known complication at the site of total hip and knee arthroplasty. Vascular involvement of this complication is rare and generally results from vascular compression by a mass or pseudotumor. In the present report, we have described a case of lower limb acute arterial ischemia due to arterial injury as a complication of metallosis with a fatal outcome.

IgG4-Related Pseudotumors Mimicking Metastases in Liver and Lungs

A 47-year-old man complained intermittent dull pain at the right upper quadrant abdomen and right neck swelling for 3 months. Blood tests revealed leukocytosis with mild eosinophilia. Computed tomography (CT) showed the presence of multiple nodules in the liver and both lung fields. Positron emission tomography/CT (PET/CT) scans found increased uptake at lymph nodes of the right neck, in the lung, liver, and prostate. The patient was diagnosed with IgG4-related disease (IgG4-RD) based on the biopsy findings from the right neck lymph nodes, showing enriched IgG4-positive lymphoplasmacytic cells. It is often difficult to distinguish IgG4-RD from malignancy, especially in presentations with multiple pseudotumors. This case serves as a reminder that IgG4-RD should be considered in earlier diagnosis, since pseudotumors in multiple organs may imitate tumor metastases.

Chest wall pseudotumor: a case of non-tuberculous mycobacterial infection

Background

Non-tuberculous mycobacterial (NTM) infections are increasing worldwide, making them an international public health problem. Surgical management is often indicated for localized infectious disease; however, most surgeons are unaware of the potential risks of transmission during surgery.

Case presentation

An 88-year-old Asian female was referred to our hospital for a tumor in the right lateral thoracic region. One month prior, she had a feeling of fullness and complained of localized pain and warmth in the right lateral thoracic wall. Pain and warmth gradually resolved without intervention; however, the fullness was getting worse. Computed tomography (CT) scan showed a mass of approximately 65 × 30 mm with an osteolytic change, involving the right 8th rib. Based on the rapid growth rate and CT findings, we strongly suspected a malignant chest wall tumor, and en bloc tumor resection with the 8th rib was performed. When the specimen was cut, a large amount of viscous pus was drained and its culture showed growth of Mycobacterium avium. Microscopically, the non-caseating epithelioid cell granuloma extended into the rib, infiltrating the bone cortex. On follow-up 1 month after discharge, there were no signs of infection or other adverse events associated with the surgery.

Conclusions

Herein, we report about a patient with a mass diagnosed as an NTM abscess involving the rib cage, which was confused with a malignant tumor and eventually diagnosed following surgical excision. This report emphasizes the need to be aware of the possibility of NTM infection and take appropriate precautions if the patient has a rapidly growing mass in the chest wall.

Sinonasal IgG4-related disease: a rare and emerging entity broadening the differential diagnosis in the sinonasal universe

BACKGROUND

IgG4-related disease (IgG4-RD) is a multi-organ immune-mediated disorder characterized by fibroinflammatory mass-forming lesions, mimicking malignancy or infection. While well-documented in salivary glands, orbit and thyroid in the head and neck, sinonasal IgG4-RD is rare.

METHODS

Cases of sinonasal IgG4-RD were retrieved, and clinicopathological features reviewed.

RESULTS

Seven cases of sinonasal IgG4-RD were identified over a 2-year period, including three males and four females, with an age range of 13-48 years (median: 32 years). Patients presented with cheek swelling, pain and visual disturbances. Serum IgG4 levels were mildly elevated. Storiform fibrosis, obliterative phlebitis and plasma cell infiltration were seen in varying proportions. Destruction of bone and subepithelial mucoserous glands was present. ALK-1 negativity distinguished from inflammatory myofibroblastic tumor.

CONCLUSION

Sinonasal IgG4-RD expands the growing spectrum of IgG4-RD. A high degree of suspicion is required to include IgG4-RD in differential diagnosis of sinonasal masses, and perform detailed histological and immunohistochemical workup for accurate diagnosis.

Retro-Odontoid Pseudotumor Formation in the Context of Various Acquired and Congenital Pathologies of the Craniovertebral Junction and Surgical Techniques

Retro-odontoid pseudotumor formation consists of an abnormal growth of granulation tissue typically posterior to the odontoid process, resulting as a manifestation of atlantoaxial instability. This instability can occur as a result of conditions ranging from severe mechanical trauma to metabolic disease or autoimmune conditions such as rheumatoid arthritis. A pseudotumor may impinge on the spinal nerves or even the spinal cord and brainstem, manifesting symptoms from severe neck pain to cervicomedullary compression or myelopathy, and in some cases even sudden death. The objective of this review is to consolidate the findings in published case reports and relevant prior literature reviews regarding the formation of retro-odontoid pseudotumor. We address the pathophysiology involved in acquired and congenital pseudotumor formation, including those associated with rheumatoid arthritis (panni). Additionally, we discuss past and current operative techniques designed to curtail and ultimately regress a retro-odontoid pseudotumor and pannus. Surgical techniques that are addressed include ventral decompression (both transoral and transnasal), dorsal decompression, and indications for posterior instrumentation in pannus formation, particularly in cases that may be sufficiently treated in lieu of an anterior approach. Finally, we will examine the role of external orthoses as both a method of conservative treatment as well as a potential adjunct to the aforementioned surgical procedures.

18F-FDOPA-PET in pseudotumoral brain lesions

INTRODUCTION

3,4-Dihydroxy-6-[¹⁸F]-fluoro-L-phenylalanine (FDOPA) positron emission tomography (PET) is sensitive for identifying primary brain tumors. However, increased FDOPA uptake has been reported in pseudotumoral brain lesions. Our aim was to analyse FDOPA-PET in patients with pseudotumoral brain lesions and to compare them with patients with brain tumors.

METHODS

We retrospectively analysed consecutively recruited patients with suspected primary brain tumor (based on clinical and magnetic resonance imaging findings) referred for FDOPA-PET in our centre between November 2013 and June 2019 (n = 74). FDOPA-PET parameters (maximum and mean lesion standardised uptake values [SUV] and ratios comparing lesion with different background uptake SUV) and thresholds were evaluated to determine which offered optimal discrimination between pseudotumoral and tumoral lesions.

RESULTS

Overlapping PET values were observed between pseudotumoral (n = 26) and tumoral (n = 48) lesion, particularly for low-grade tumors. Based on receiver operating characteristic (ROC) analyses, the optimal PET parameters to discriminate pseudotumoral from tumoral lesions were SUV_max lesion/basal ganglia, SUV_max lesion/grey matter, SUV_mean lesion/grey matter, and SUV_max lesion/mirror area in contralateral hemisphere (all ratios showing area under the curve [AUC] 0.85, 95% CI). The narrowest 95% sensitivity-95% specificity window was observed for SUV_max lesion/basal ganglia ratio, with ratio values of 0.79 and 1.35 corresponding to 95% sensitivity and 95% specificity, respectively.

CONCLUSION

FDOPA-PET uptake should be interpreted with caution in patients with suspected primary brain tumor, especially in patients showing low or intermediate SUV values and ratios. CLINICAL TRIAL REGISTRATION-URL: https://www.clinicaltrials.gov . Unique identifier: NCT04306484.

Retro-odontoid Pseudotumor: Two Cases of Intradural Ganglion Cysts Arising From the Odontoid Process with Syringobulbia

BACKGROUND

Ganglion cysts mostly occur in the knuckles and wrists, but they rarely present in the odontoid process and can cause neurological symptoms by compressing the spinal cord. They are mostly localized in the epidural space, but may very rarely appear in the intradural space. There are no reports of cases of intradural ganglion cyst involving syringobulbia.

CASE DESCRIPTION

We report the presentation and management of 2 cases of an intradural ganglion cyst of the odontoid process. Several treatment options for ganglion cysts of the odontoid process have been reported, such as rest and use of a neck collar, posterior decompression and fusion, and transoral anterior decompression. Because our 2 cases progressed rapidly and had severe neurological symptoms, surgical treatment was performed for rapid decompression and definitive pathological diagnosis. The mass was resected as much as possible using the lateral occipital fossa approach, and the operation was completed without dissection of the brain stem or manipulation of the syringobulbia. Postoperatively, neurological symptoms promptly improved, and the syringobulbia reduced.

CONCLUSIONS

For intradural ganglion cysts with syringobulbia, we suggest relief of the compression by resection of the mass and treatment of the syringobulbia in 2 stages, if necessary, to avoid the risk of damage to the brainstem.

Do Polyethylene Supra-Macroparticles Lead to Pseudotumor Formation in Metal-on-Polyethylene Total Hip Arthroplasty?

We describe 2 cases of pseudotumors induced by an unusual size of polyethylene wear particle after metal-on-polyethylene total hip arthroplasty (MoP THA). The supra-macroparticles of size >100 μm originated from a polyethylene liner with relatively small cup anteversion, potentially leading to excessive loading and increased wear of the anterior edge of the polyethylene liner. Histopathology showed a foreign-body reaction to the polyethylene particles without an adverse reaction to metal debris and with no severe signs of corrosion at the head-neck junction, which have been noted in past reports of pseudotumors in MoP THA. It has been suggested that the large polyethylene wear particles might be the cause of pseudotumor formation in MoP THA.

"Bumpy" ride for the female cyclist: A rare case of perineal nodular induration, the ischial hygroma

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PNI is a pseudoneoplastic lesion caused by repetitive microtrauma.

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Shearing in perineal fascia stimulates fibroblastic proliferation.

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Reported almost exclusively in males, it can occur in females and is underdiagnosed.

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Cyclists and any saddle sport athletes (even seated lawnmowing) are at risk.

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Treatment is to remove the trigger; surgery can be considered in refractory cases.

Introduction

Cycling is known to cause groin pain, typically adductor/hamstring strains and “saddle sores” (skin abrasion, ulceration and/or folliculitis). Rarely does it result in pathological mesenchymal lesions.

Presentation of case

We report a case of a 52-year-old female avid cyclist with chronic groin pain. Activity alteration, bike fit, and saddle modification did not ameliorate her symptoms. MRI revealed no hamstring or bony abnormality but demonstrated low T1/high T2 signal in the right perineum inferior to the ischial tuberosity.

Discussion

Perineal nodular induration, or “cyclist’s nodule,” is a reactive fibroblastic and myofibroblastic pseudotumor almost exclusively reported in male cyclists. PNI can become so nodular that it has even been referred to as an accessory testicle or “the cyclist’s third testicle.”

Conclusion

We report an unusual case of PNI in a female cyclist and review the differential diagnosis of non-infectious soft tissue perineal pain in cyclists. Clinicians should be aware of this rare condition to avoid confusion with other mesenchymal lesions.

Rare presentation of inflammatory myofibroblastic tumor in the kidney

Inflammatory myofibroblastic tumor (IMT) is a rare pathologic entity that has been mostly described in the lung. It has been reported in nearly every organ, with occurrence in the kidney being extremely rare. IMT has nonspecific clinical and radiological findings and often mimics a malignant process. This is a case discussing the radiologic and pathologic findings of a renal IMT in a 35-year-old female who underwent radical nephrectomy for a right renal pelvis mass that was mistaken for transitional cell carcinoma.

Cobalt hip prosthesis intoxication mimicking an autoimmune disease

Cobalt-containing hip prosthesis may cause systemic toxicity due to the release of cobalt from metal-on-metal (MoM) joint arthroplasty into the bloodstream. High cobalt blood levels can lead to a variety of clinical manifestations, mimicking other disorders, especially autoimmune, hematologic, and infectious diseases. Our purpose is to describe a clinical case of cobalt hip prosthesis intoxication mimicking an autoimmune disease, with systemic inflammation signs, arthro-myalgias unrelated to overt synovitis, and multiple autoantibody positivity. A 69-years-old woman presented with a 1-year history of right coxalgia, recurrent fever, arthro-myalgias, mediastinal and right iliac reactive lymphadenopathy. She underwent hip replacement surgery seven years earlier. The physical examination was unremarkable except for right hip pain. Laboratory tests showed markedly increased inflammatory indices and microbiological tests were all negative. Ultrasound-guided arthrocentesis of right hip yielded limpid fluid with negative cultures. Increased cobalt levels in plasma and urine showed metal intoxication. Magnetic resonance imaging with metal artifact reduction sequence (MARS) confirmed a periprosthetic mass as usually seen in reaction to metal debris. Prosthesis substitution was performed with a resolution of the clinical picture and normalization of cobalt levels.

Orbital diseases mimicking graves' orbitopathy: a long-standing challenge in differential diagnosis

Graves' orbitopathy (GO) is the most common cause of orbital tissue inflammation, accounting for ~ 60% of all orbital inflammatory conditions in the population aged 21-60 years, and for ~ 40% in the population aged > 60 year. GO is observed in 25-30% of patients with Graves' hyperthyroidism and more rarely in association with hypothyroid autoimmune thyroiditis. In addition, a small proportion of GO patients (1-2%) do not have a clinically overt thyroid dysfunction. Clinically, GO is characterized by proptosis, inflammation involving the eyelids and the conjunctiva, extraocular muscle hypertrophy, with consequent reduction of ocular motility and diplopia, and in the most severe cases, compression of the optic nerves at the orbital apex, with reduction of visual acuity. At CT scan or MRI, a muscle increase involving the superior, medial and inferior rectus is quite typical. In the most severe forms, compression of the optic nerves at the orbital apex can be observed. Euthyroid GO is usually an early sign of a full-blown Graves' disease; however, in some cases, the orbital disease can remain isolated. Moreover, euthyroid GO can rarely be unilateral, which makes the picture even more confusing. Under those circumstances, the diagnostic process becomes obviously quite difficult, having other conditions mimicking GO been excluded. A number of inflammatory conditions affecting orbital tissue can mimic GO, thereby requiring an accurate evaluation for a proper differential diagnosis. The majority of these conditions are immune mediated. Most of them are benign, but they can be rather aggressive and some can cause visual loss. The most common inflammatory condition affecting orbital tissues and mimicking GO is idiopathic orbital inflammation. Other, more rare, orbital diseases that should be considered in the differential diagnosis are infections, orbital manifestations of systemic diseases, primitive and secondary orbital neoplasms, and orbital vascular alterations. In most instances, when an orbitopathy occurs in the absence of hyperthyroidism, the diagnosis of the disease underlying the ocular symptoms and signs is based on exclusion of the other conditions. Here we review the conditions that can mimic GO and how to distinguish them from this obnoxious eye disease.

Regenerative hepatic pseudotumor: a new pseudotumor of the liver

Cases of new pseudotumors of the liver were collected from multiple medical centers. Four resection and 4 biopsy specimens were collected, including 4 women and 4 men at an average age of 48 ± 15 years (range: 28-73 years). The lesions were visible on imaging but were either ill-defined or had indeterminate features for characterization. They ranged in size from 2 to 9 cm and were multiple in five cases. The resection specimens showed lesions that had vague borders but were visible in juxtaposition to the normal liver on gross examination. Histologically, the lesions also had ill-defined borders and were composed of benign reactive liver parenchyma. Central vein thrombi were seen in 5 cases, and portal vein thrombi, in 2 cases. These vascular changes were associated reactive parenchymal changes including sinusoidal dilation, patchy bile ductular proliferation, and portal vein abnormalities. All lesions lacked the histological findings of hepatic adenomas, focal nodular hyperplasia, or other known tumors and pseudotumors of the liver. In summary, this study provides a detailed description of a new pseudotumor of the liver: a reactive, hyperplastic mass-like lesion that forms in association with localized vascular thrombi, for which we propose the term regenerative hepatic pseudotumor. This lesion can closely mimic other benign or malignant hepatic tumors on imaging and histology.

Disseminated cytomegalovirus infection with bilateral adrenal pseudotumors masquerading as recurrent hematologic malignancy

BACKGROUND

Mass-like lesions are an uncommon presentation of cytomegalovirus (CMV) disease.

CASE

We report on a case of disseminated CMV disease with bilateral adrenal pseudotumors in a patient with a history of acute leukemia in remission.

CONCLUSION

In the settings of advanced cancer therapy and organ transplantation, a high index of suspicion for CMV should be maintained for mass-like disease.

Pseudotumor recurrence in a post-revision total hip arthroplasty with stem neck modularity: A case report

BACKGROUND

This unique presentation of hip swelling is only the seventh reported case of pseudotumor recurrence in a non-metal-on-metal total hip arthroplasty (THA) construct. The constellation of patient symptoms and laboratory findings contradict the expected elevated serum metal ion levels associated with the formation of pseudotumor. The presentation, lab trends, and imaging findings contribute to the growing base of knowledge surrounding the effects of corrosion in arthroplasty constructs with stem-neck modularity.

CASE SUMMARY

A 74-year-old man status post primary THA presented with left hip swelling and elevated serum metal ions five years after implantation of a modular stem-neck prosthesis. The swelling was diagnosed as pseudotumor based on laboratory trends and imaging findings and was treated with revision arthroplasty that completely resolved the initial hip swelling. The patient presented with recurrent hip swelling and recurrent pseudotumor findings on imaging in the same hip four months later. Non-operative management with ultrasound-guided hip aspiration resulted in symptom relief and resolution of the recurrent swelling. After one year of follow-up, the patient had no further recurrences of hip swelling.

CONCLUSION

This case of post-revision pseudotumor recurrence elucidates attributable patient, surgical, and implant factors with a discussion of diagnostics, management, and prognosis for patients with pseudotumor in non-metal-on-metal arthroplasty constructs.

Metal-on-metal total hip arthroplasty adverse local tissue reaction with intermittent unilateral vascular claudication

Osteolysis and adverse local soft-tissue reactions are well-documented complications of metal-on-metal prosthetic implants. This case report describes a 68-year-old man who presented to the clinic 10 years after staged bilateral metal-on-metal total hip arthroplasty revisions with the primary complaint of groin pain, intermittent right leg pain, swelling, and muscle cramping while ambulating that resolved with rest. A complete workup was negative for deep venous thrombosis and infection. His symptoms were found to be secondary to an iliopsoas bursal mass externally compressing the femoral vasculature resulting in vascular claudication. He was treated with revision arthroplasty and drainage of the fluid within the iliopsoas bursal effusion with symptomatic resolution.

Intracranial Multiple Pseudotumor Due to Immunoglobulin G4-Related Disease without Other Lesions: Case Report and Literature Review

BACKGROUND

Immunoglobulin (Ig)G4-related disease (IgG4-RD) was defined only recently and can be found in many organs. As intracranial lesions, hypophysitis and pachymeningitis are well known, whereas intracranial pseudotumor is unusual. This case involved multiple intracranial pseudotumors without extracranial lesions, mimicking multiple meningioma.

CASE DESCRIPTION

A 72-year-old woman was referred to our hospital with an incidental mass lesion at the craniocervical junction on magnetic resonance imaging (MRI). MRI showed diffuse enhanced extra-axial nodules around the medulla and middle cranial fossa. Surgery was performed for the gradually enlarging tumor. Intraoperative findings showed hard nodules around the vertebral artery. We performed subtotal resection. Neuropathological findings showed diffuse lymphoplasmacytic infiltration with lymphoid follicles. Immunohistochemical studies for IgG4 and IgG showed the histological criteria for IgG4-RD were met. Given the high IgG4 serum level, we diagnosed IgG4-RD. Steroid was administered initially but was then tapered, and nodules have since remained small.

CONCLUSIONS

This case demonstrates IgG4-RD mimicking meningioma with multiple masses but without extracranial lesions. This case and previous descriptions suggest the possibility of pseudotumor due to IgG4-RD in the presence of multiple extra-axial lesions at the dura and supplying artery, hard nodules with thickening of the artery, and frozen section findings of lymphoplasmacytes surrounded by rich collagen fibers. In such cases, the pseudotumor due to IgG4-RD should be resected, and total resection might not be warranted.

Common and uncommon features of nephrogenic adenoma revisited

Nephrogenic adenoma is a common diagnosis in urological pathology that may be challenging for general pathologists. Due to its polymorphic appearance under the microscope, some cases can be misdiagnosed as malignancy and then unnecessarily overtreated. Aside from the typical tubules, cysts and papillae, nephrogenic adenoma may display a broad spectrum of histologic appearances and locations, some of them atypical or unexpected. These unusual and concerning features will have special consideration in this description. The goal of the review is to increase awareness of general pathologists of the varied histology of nephrogenic adenoma.

Severe Wear and multiple Pseudotumor formation due to revision for ceramic head breakage after ceramic-on-ceramic Total hip arthroplasty: a case report

Background

Head breakage is a serious complication following total hip arthroplasty when using Ceramic on Ceramic bearings surfaces. There is still in controversy about the selection of bearing surfaces when conducting revision surgery.

Case presentation

We describe the case of a fifty-year-old man who had undergone right total hip arthroplasty (THA) with ceramic-on-ceramic prostheses in 2011. After a fall 6 years after the primary procedures, radiographs suggested a ceramic head breakage for revision THA with exchange of metal-on-polyethylene bearing. However, 8 months later, severe metallosis and multiple pseudotumor was confirmed in pelvis and surrounding hip after re-revision THA with ceramic-on-polyethylene prostheses. Analysis of the serum metal ion indicated massive wear of the metal head and erosion of the stem neck and taper.

Conclusions

This case vividly demonstrates metal bearings should be avoided and revision with complete synovectomy and thorough debridement should be performed whenever possible for a fractured ceramic bearing.