OBJECTIVE: To describe the rare process of osteolytic labyrinthitis, previously referred to as labyrinthine sequestrum, which involves progressive obliteration of the bony and membranous labyrinth with eventual supplantation with soft tissue and, in some cases, bony sequestrum.
METHODS: Three patients with diverse presentations of osteolytic labyrinthitis from two tertiary care academic medical centers.
METHODS: Case series report analyzing the relevant clinical, radiologic, pathologic, and surgical data on our patients with osteolytic labyrinthitis and comparing these index cases to the existing literature.
METHODS: We describe the varying image findings seen in osteolytic labyrinthitis on computed tomography and magnetic resonance imaging. Also, we report successful surgical intervention and hearing rehabilitation with cochlear implantation in patients with osteolytic labyrinthitis.
RESULTS: Our three patients presented with profound sudden sensorineural hearing loss and vertigo consistent with labyrinthitis. None of the three patients had a history of chronic otitis media. Imaging workup revealed varying degrees of erosion to the otic capsule bone demonstrating the spectrum of disease seen in osteolytic labyrinthitis. Although two cases showed osteolytic changes to the semicircular canals and vestibule, the first case revealed frank bony sequestrum within the obliterated labyrinth. The three cases were taken for surgical debridement and cochlear implantation.
CONCLUSIONS: We propose the new term, osteolytic labyrinthitis-previously referred to as labyrinthine sequestrum-to describe the rare spectrum of disease characterized by destruction of the osseous and membranous labyrinth and potential supplantation with bony sequestrum. Cochlear implantation is a viable option in selected patients with osteolytic labyrinthitis.

Osteolytic lesions refer to the destruction of any part of bone due to a disease process (pertaining to dissolution of bone, especially loss of calcium). Osteomyelitis is the inflammation of the bone caused by an infecting organism. Although bone is normally resilient to bacterial colonization, events such as trauma, surgery, infections, the presence of foreign bodies, and anemia may disrupt bony integrity and lead to the onset of bone infections. Sometimes, osteomyelitis causes no signs and symptoms or the signs and symptoms are hard to distinguish from other problems. This may be true for children, older adults, and people whose immune systems are compromised. Here, we report a case of chronic intermedullary inflammation of bone in a child.

Multicentric carpotarsal osteolysis syndrome (MCTO) is a rare skeletal disorder characterized by progressive osteolysis involving the carpal and tarsal bones, and often associated with nephropathy. It is caused by heterozygous mutation in the MAF bZIP transcription factor B (MAFB) gene. Heterogeneous clinical manifestation and wide spectrum of disease severity have been observed in patients with MCTO. Here, we report a case of a male patient who presented with kidney failure in childhood with progressive disabling skeletal deformity. He was diagnosed with MCTO at 31-years-old, where a de novo pathogenic heterozygous variant in NM_005461.5:c.212C>A: p.(Pro71His) of the MAFB gene was identified. While there has been little data on the long-term prognosis and life expectancy of this disease, this case report sheds light on the debilitating disease course with multiple significant morbidities of a patient with MCTO throughout his lifetime of 33 years.

BACKGROUND: Multicentric carpotarsal osteolysis (MCTO) is a rare genetic disorder characterized by the progressive loss of bone in the hands, feet, and other skeletal structures. It presents with symptoms that may resemble those of juvenile idiopathic arthritis, making diagnosis challenging for clinicians. The identification of MAF BZIP Transcription Factor B (MAFB) mutations as significant contributors to MCTO represents a major breakthrough in our understanding of the pathogenesis of this rare skeletal disorder.
METHODS: Our objective was to present the phenotype, treatment, and outcome of a patient with a variant of MAFB-induced MCTO to broaden the range of clinical features associated with MCTO and share our clinical experience for improved diagnosis and treatment. In our case, early MRI examination of the bones and whole exome sequencing enabled an early and accurate MCTO diagnosis, and timely Denosumab administration resulted in no deterioration.
CONCLUSIONS: This suggests that MRI examination and whole exome sequencing should be considered when MCTO is suspected, and Denosumab might be an option in the treatment of MCTO.

An 11-year-old, female-neutered beagle was presented with a growing soft tissue mass arising within the deep tissues of the left cranial cervical region. At presentation, facial asymmetry was evident along with palpable lymphadenomegaly. Magnetic resonance imaging demonstrated a locally invasive cervical mass with intracranial invasion through focal osteolysis of the occipital bone. After antihistamine administration, cytology confirmed mast cell tumour (MCT) with metastasis to local lymph nodes and liver. The owner chose to pursue lomustine and prednisolone, which were dispensed, but, before home administration, prolonged seizures/status epilepticus occurred prompting euthanasia. Postmortem examination confirmed a high-grade MCT associated with, and infiltrating through, muscle, calvarium, dura mata, leptomeninges and the underlying brain. We present the clinical, imaging, and pathological findings of an unprecedented case of extracranial MCT tumour causing osteolysis of an imperforate flat bone (occipital bone) and intracranial invasion.

Although bone destruction and hypercalcemia without acute peripheral blast BCR-ABL-positive acute lymphoblastic leukemia (ALL) have been reported in children, they are rare in adults. Herein, we describe a case of BCR-ABL positive ALL with a triploid karyotype, WT1, and CDKN2A mutations with hypercalcemia and bone destruction as the first manifestations. Complete remission (CR) was achieved by induction chemotherapy. BCR-ABL turned negative after treatment with dasatinib. However, computed tomography and whole-body bone scan showed extensive bone destruction. Additionally, bone biopsy showed leukemic infiltration. After treatment with dasatinib and VMCP, leukemia recurred with positive BCR-ABL. The T315I mutation occurred. The patient was surgically diagnosed with calculous cholecystitis and achieved CR2 by postoperative orebatinib and VP regimens. Later, the patient died due to a severe pulmonary infection. BCR-ABL-positive ALL with bone destruction is rare and difficult to control using tyrosine kinase inhibitor chemotherapy alone. Therefore, further exploration of more effective treatments is needed.

Pancoast tumors, also known as superior sulcus tumors, encompass a diverse spectrum of neoplasms that infiltrate the apex of the chest wall, yielding distinctive clinical presentations. One of the earliest signs of tumor growth is pain radiating to the upper limb, stemming from peripheral nerve involvement, which can mimic joint pain or spinal radicular irritation. In this case report, we present the clinical history of a 64-year-old female smoker who had previously been recommended for orthopedic elbow surgery due to epicondylitis. Subsequent to the development of additional symptoms and rigorous investigation, a Pancoast tumor was diagnosed. Furthermore, we discuss the characteristic treatment modalities available for Pancoast tumors, including pharmacological pain management and interventional strategies such as spinal cordotomy and spinal alcoholysis. This case underscores the significance of recognizing atypical presentations and emphasizes the importance of comprehensive evaluation in the diagnosis and management of Pancoast tumors.

UNASSIGNED: Ovarian cancer with bone involvement occurs rarely with an incidence of 0.1-0.12%. The common sites of bone metastasis are vertebrae, pelvic bones, and the skull. Patients present with severe localized bone pain, swelling, and difficulty in walking. We report a rare case of a 53-year-old female with metastatic epithelial serous adenocarcinoma of the ovary presented with multiple bony lesions in pelvic bones involving the sacrum, bilateral ilium, ischium and pubic bones and the right femur in the region of greater trochanter, smaller lesions in the left femur, and dorso lumbar vertebral metastasis while undergoing treatment as a part of distant spread. Radiologically, the osteolytic lesions are the most common, but in our case, the lesions are osteoblastic, which is rare.

Numerous interference screws of different compositions exist including titanium screws, bioabsorbable screws, and polyetheretherketone (PEEK) screws. PEEK-based implants are frequently used in orthopaedic surgery due to their biocompatibility, similar elastic modulus to cortical bone, and purported negligible risk of osteolysis compared with bioabsorbable screws. In this case report, we present the case of a 48-year-old healthy female who experienced a massive osteolytic reaction in the talus and fibula after 11 weeks following implantation of PEEK-based interference screws during lateral ankle ligament reconstruction. The patient subsequently underwent removal of the PEEK screws and specimens were sent for microbiological and histopathological analysis. The specimens report demonstrated fibrotic tenosynovial soft tissue with patchy chronic inflammation, oedematous reactive changes, and histiocytic reaction, with no evidence of any significant acute inflammation. The patient recovered well and was asymptomatic at 6 months postoperatively. To our knowledge, this is the first case report of a massive osteolytic reaction to PEEK-based interference screws.

We present the clinical and radiological characteristics of phalangeal microgeodic syndrome in a cluster of five children during the second peak of COVID-19 pandemic in the UK. Each child presented with phalangeal swelling and erythema, prompting a comprehensive multi-disciplinary team review to analyse the clinical presentation, blood test results and imaging. The cohort\'s average age was 14.1 years, ranging from 10.4 to 16.6 years, with two girls and three boys. Four children experienced phalangeal involvement in the hands, whilst one was affected solely in the feet. A rheumatological work-up was performed for all. Hand X-rays performed on three children revealed distinct radiographic features like microgeodes, subperiosteal bone resorption and rarefaction in two cases. However, further MRI showed extensive changes closely correlated with the clinical signs of cutaneous vasculopathic rashes. The MRI abnormalities were notable, encompassing marrow oedema primarily affecting metaphyses and epiphyses, displaying broad transition zones. Soft tissue swelling and cortical erosions were also observed. These MRI features proved more pathognomonic in the acute clinical context. The study concluded that phalangeal microgeodic syndrome, characterised by digital swelling and erythema, might not be adequately assessed by plain X-rays. The more comprehensive MRI features, including marrow oedema and soft tissue abnormalities, appeared to be more indicative in diagnosing the condition. Considering the rarity of this syndrome and its temporal association with the COVID-19 pandemic, the study hypothesised that COVID-related thrombophilia and immune-mediated vasculopathy might act as crucial triggers for the active bony manifestations seen in this syndrome. KEY POINTS: • PMS is a rare, predominantly paediatric condition, of unknown aetiology which affects the digits. • Laboratory investigations are generally negative; however, in the appropriate clinical context, the X-ray findings of microgeodes and pattern of bone marrow oedema seen on MRI are pathognomonic. • Considering the rarity of PMS and temporal association with the COVID-19 pandemic, COVID vasculopathy may represent a previously unrecognised aetiology for PMS.