Atypical Bone Research Articles

Atypical Bone Involvement in Erdheim-Chester Disease Showing No or Subtle Structure Changes and Increased Activity on FDG PET/CT.

Bones are the most common sites involved in Erdheim-Chester disease. On imaging, the bone involvement in Erdheim-Chester disease typically presents as osteosclerotic lesions, and osteolytic lesions are unusual. Bone lesions showing no or subtle structure changes are rarely reported. We describe FDG PET/CT findings in a case of Erdheim-Chester disease with atypical bone involvement. The bone lesions showed no or subtle structure changes without obvious osteosclerosis or osteolysis on radiographs and CT, and increased FDG activity mimicking lymphoma. Familiarity with these atypical imaging findings of bone involvement in Erdheim-Chester disease is helpful for the diagnosis.

Spinal Manifestations of Skeletal Dysplasia: A Practical Guide for Clinical Diagnosis.

Skeletal dysplasias are a group of genetic conditions defined by atypical bone or cartilage growth and development. Skeletal abnormalities include short stature, limb deformity, joint contracture, and spinal deformity. Over 90% of disorders have a known genetic mutation that can definitively determine the diagnosis. As patients may present with a primary spinal concern, a careful clinical and radiographic evaluation can allow the physician to develop a working diagnosis to guide additional evaluation. Spinal manifestations include scoliosis and kyphoscoliosis, cervical instability, cervical kyphosis, thoracolumbar kyphosis, spinal stenosis, and atypical vertebral body morphology. An understanding of the affected conditions, prevalence, and natural history of these radiographic findings aids the orthopaedic surgeon in establishing a diagnosis and guides appropriate orthopaedic care.

The aetiology of atypical bone health in individuals with Down syndrome.

Trisomy 21 (T21), more commonly known as Down syndrome (DS) is a genetic condition where every cell in the body has an additional copy of chromosome 21. Despite improvements in our management of DS-associated health risks, we still do not understand how T21 impacts human bone health. This is a critical area of research owing to increased life expectancy of people with DS, and the predisposition of individuals with DS to early-onset osteoporosis and osteopenia. We have conducted a scoping review using the methodological framework of Arksey and O'Malley (2005) which analysed the existing data on bone growth, development, maintenance and repair in T21 using the Medical Subject Headings (MeSH) terms: Trisomy 21, Down syndrome, Down's syndrome, bone development, bone growth, bone maintenance, fracture risk, osteoporosis, bone mineral density, bone strength, bone mineral content, bone formation, bone repair, osteoblast, osteoclast, osteocyte, osteomacs. A total of 31 papers were identified. After screening, 16 articles were included in full-text review. There was a total of eleven in vivo animal model studies identified and included in the scoping review. Of those eleven, ten revealed a difference in bone growth and development in animal models of DS, and two found that bone maintenance and repair in animal models of DS is reduced with both studies reporting an osteoporotic bone phenotype in male and female mice. All five studies that included human participants reported impacts on bone growth and development with reduced bone growth rates and delayed bone maturation in individuals with DS. At the time of review, there were no human studies directly investigating bone maintenance and repair in individuals with DS. We found documented evidence that T21 impacts bone growth and development, maintenance and repair in both animal models and human studies.

Unusual metastases of breast cancer: a single-center retrospective study

Objectives: While clinical and radiological awareness of the usual, frequent metastatic sites of breast cancer is high, unexpected 'atypical' localisations may be more easily overlooked in the cancer management process. The aim of this article is to contribute to this awareness in order to facilitate and improve the diagnosis and follow-up of breast cancer. Methods: In this study, we retrospectively evaluated breast cancer patients who were diagnosed and followed up between 2017 and 2022 in our hospital, which is an important oncology center. Results: Of the 852 patients included in this study, 79 had an unusual metastasis localization. The most common unusual metastasis sites were mediastinal lymph nodes and brain. These sites were followed by atypical bone involvement, mesenteric lymph nodes, cervical lymph nodes, hilar lymph nodes and surrenal metastases. The most rare metastases were more common in the uterus and ovary, followed by pancreas, parotid gland, spleen, colon, pericardium-atrium, orbital soft tissues and lacrimal gland. . The unusual site of metastasis was mediastinal lymph nodes in 17.7% (n = 14), brain in 17.7% (n = 14), atypical bone sites in 12.6% (n = 10), mesenteric lymph nodes in 11.3% (n = 9), cervical lymph nodes in 11.3% (n = 9), hilar lymph nodes in 5% (n = 4) and surrenal in 6.3% (n = 5). Conclusions: Sharing knowledge and experience about unusual metastases of breast cancer will contribute to the diagnosis and treatment of metastatic diseases by increasing the awareness of this issue. For this, multicentre studies should be conducted to combine these experiences.

The CBCT Retrospective Study on Underwood Septa and Their Related Factors in Maxillary Sinuses-A Proposal of Classification.

Introduction. The presence of bone septum in the maxillary sinus is one of the most common anatomical findings. So-called Underwood septa (US) are an atypical bone formation in the maxillary sinuses. Mostly they are quite easily found in CBCT studies and have major importance in sinus lift procedures in dental surgery. Furthermore, the shape, location, and size of the bony septa are important in each maxillary sinus surgery. Material and methods. A retrospective study of 120CBCT scans from the authors' own database was conducted. Results. Approximately 37.5% of each CBCT was associated with the occurrence of US, while just 25% had a full septum, and a total of only 14 patients had a half septa. More females have US, while healthy pneumatized maxillary sinus is most commonly found (82.22%). There is no correlation between the occurrence of silent sinus syndrome (p = 0.174), mucosal thickening (p = 0.325), or retention cyst formation (p = 0.272). Most sinuses are without any opacification in CBCT evaluation (91.11%), while other syndromes are not statistically relevant. Conclusions. It seems that the occurrence of Underwood septa is not statistically related to any clinical, radiological, or pathological condition within the sinus (p > 0.05). Furthermore, a more full or partial appearance of US was found in female patients.

Atypical skeletal involvement in patients with Erdheim\u2013Chester disease: CT imaging findings

ObjectivesTo review retrospectively atypical bone findings from computed tomographic (CT) imaging in patients with Erdheim–Chester disease.MethodsAll 28 patients with Erdheim–Chester disease (13 men and 15 women; mean age, 45 years; range, 7–63 years) underwent chest-abdomen-pelvis CT. CT images were reviewed and analyzed for the various features of atypical bone lesions by two radiologists in consensus.ResultsTwenty-one patients had atypical bone involvement. Radiologically, these atypical osseous lesions were categorized into three types: diffuse, nodular and patchy. Eleven (52%) of the 21 patients had spinal lesions, of which four (36%) had the diffuse type, eight (73%) had the nodular pattern, and six (55%) had the patchy pattern. Sixteen (76%) of the 21 patients had pelvic involvement, of which two (13%) were diffuse, nine (56%) were nodular and 11 were (69%) patchy. Ribs were involved in seven (33%) of the 21 patients, with the nodular pattern in one (14%) patient and the patchy type in six (86%) patients. Clavicle involvement was seen in nine (43%) of the 21 patients, of which the diffuse type was found in only one (11%) patient, the nodular type in six (67%) patients, the solitary patchy type in four (44%) patients. Sternum involvement was seen in 10 (48%) of the 21 patients and all were nodular.ConclusionsThis series provides a detailed description of atypical bone involvement in Erdheim–Chester disease which on CT displays three major patterns. Understanding these patterns may help increase the accuracy of diagnosis of this disease.

3D-printed Patient-specific Spine Implants: A Systematic Review.

Systematic review. To review the current clinical use of 3-dimensional printed (3DP) patient-specific implants in the spine. Additive manufacturing is a transformative manufacturing method now being applied to spinal implants. Recent innovations in technology have allowed the production of medical-grade implants with unprecedented structure and customization, and the complex anatomy of the spine is ideally suited for patient-specific devices. Improvement in implant design through the process of 3DP may lead to improved osseointegration, lower subsidence rates, and faster operative times. A comprehensive search of the literature was conducted using Ovid MEDLINE, EMBASE, Scopus, and other sources that resulted in 1842 unique articles. All manuscripts describing the use of 3DP spinal implants in humans were included. Two independent reviewers (N.W. and N.E.S.) assessed eligibility for inclusion. The following outcomes were collected: pain score, Japanese Orthopedic Association (JOA) score, subsidence, fusion, Cobb angle, vertebral height, and complications. No conflicts of interest existed. No funding was received for this work. A total of 17 studies met inclusion criteria with a total of 35 patients. Only case series and case reports were identified. Follow-up times ranged from 3 to 36 months. Implant types included vertebral body replacement cages, interbody cages, sacral reconstruction prostheses, iliolumbar rods, and a posterior cervical plate. All studies reported improvement in both clinical and radiographic outcomes. 11 of 35 cases showed subsidence >3 mm, but only 1 case required a revision procedure. No migration, loosening, or pseudarthrosis occurred in any patient on the basis of computed tomography or flexion-extension radiographs. Results of the systematic review indicate that 3DP technology is a viable means to fabricate patient-matched spinal implants. The effects on clinical and radiographic outcome measures are still in question, but these devices may produce favorable subsidence and pseudoarthrosis rates. Currently, the technology is ideally suited for complex tumor pathology and atypical bone defects. Future randomized controlled trials and cost analyses are still needed. IV-systematic review.

Atypical Clinical Picture of Breast Cancer with Dominant Symptoms of Hematologic and Gastrointestinal Malignancies

Gastrointestinal malignancy was suspected in a 68-year-old woman with long-term anemia, thrombocytopenia, leukopenia, the presence of fecal occult blood and elevated levels of CEA and CA 19-9. However, malignancy was not confirmed. The patient was later hospitalized in the Department of Hematology where hematologic disease was excluded. Cervical and inguinal lymphadenopathy and atypical bone marrow cells collected by aspiration biopsy gave rise to the suspicion of bone marrow involvement by tumor cells of non-hematologic origin.

A rare case of chronic nonbacterial osteomyelitis of the mandible in a young adult male

Chronic nonbacterial osteomyelitis (CNO), also known as chronic recurrent multifocal osteomyelitis, is a rare disease of unknown etiology mainly affecting girls with a mean age of 10 years. The disease is characterized by nonbacterial osteolytic lesions and swelling of the adjacent soft tissues and has nonstandard treatment protocols. Unifocal CNO typically involves the mandible. Mandibular CNO is difficult to differentiate from bacterial osteomyelitis because of its similar radiographic profile and clinical symptoms. Therefore, magnetic resonance imaging (MRI) should be considered if infectious osteomyelitis has not been diagnosed by laboratory examination. Our patient was a young adult man with mandibular CNO presented with atypical bone fragments on MRI. Clinical symptoms improved within 3 days after surgical intervention to remove the fragments and treatment with a nonsteroidal anti-inflammatory drug (NSAID). NSAID therapy was discontinued at postoperative day 20, and the patient has experienced no recurrences at 5 months after surgery.

Therapeutic Dimensions of Bisphosphonates: A Clinical Update.

Bisphosphonates (BPs) are a commonly used class of drugs for the treatment of bone disorders. An extensive review of BPs with their clinical efficacy and safety profile is unavailable. This study aimed to review the available literature on BPs, summarize their role in clinical therapy, and emphasize their safety profile. Authors reviewed the existing literature using the Google Scholar, PubMed, and Micromedex databases and analyzed the collected articles. BPs are the preferred medication for osteoporosis and other similar conditions owing to their efficient antiosteoclastic activity. Few of them are available in oral dosage forms; hence, they are patient-friendly. The mechanism of action, common adverse effects and their clinical applications, precautions and warnings pertaining to the route of administration, and safety profiles have been discussed in this manuscript. The common adverse effects are majorly related to the gastrointestinal, cardiovascular, and endocrine system. Upon chronic usage, patients may experience serious problems like osteonecrosis of the jaw and atypical bone fractures. Although BPs are effective and safe, they may cause GI adverse effects and rare cases of osteonecrosis. Patient counseling could prove beneficial in early identification and prevention of the adverse effects associated with BPs.

Nutrient foramen of clavicle an anatomical and a topographic study

Nutrient foramen of clavicle an anatomical and a topographic study - IJCAP- Print ISSN No: - 2394-2118 Online ISSN No:- 2394-2126 Article DOI No:- 10.18231/j.ijcap.2019.099, Indian Journal of Clinical Anatomy and Physiology-Indian J Clin Anat Physiol

Research progress on subchondral bone lesions in degenerative knee osteoarthritis

The role of the subchondral bone in the pathophysiological processes of knee osteoarthritis(KOA)is receiving increasing attention.During the early stages of KOA, micro-fractures due to stress occurr with increased subchondral bone remodeling and decreased subchondral bone structural parameters, promoting the development of local microcirculatory disorders and atypical bone marrow lesions(BMLs). The micro-pores in cartilage provide pathways for blood vessel invasion into the deep layers of articular cartilage and subsequently bring in cartilage-degrading enzymes.With the pathogenesis of KOA, the loss of proteoglycans, which resist pressure to maintain the integrity of articular cartilage, results in stress overloading and then metabolic imbalances, leading to decreased bone resorption and increased bone formation.In the late stages of KOA, significant subchondral bone sclerosis further obstructs local blood microcirculation, which manifests as extended BMLs or increased signal intensity and even subchondral bone cysts.The acidic local environment impairs osteoblast function and erodes bone strength, contributing to subchondral bone collapse.Consequently, there is continued loss of the attached articular cartilage because of the positive feedback.Drug or surgical treatment aimed at cartilage protection should focus on functional modulation of osteoblasts and/or osteoclasts in the subchondral bone and the internal environment at different stages, instead of merely on the protection of articular cartilage. Key words: Cartilage; Osteoarthritis; Knee

Intravoxel incoherent motion diffusion MR and diffusion kurtosis imaging for discriminating atypical bone metastasis from benign bone lesion.

Objectives:To investigate the feasibility of intravoxel incoherent motion (IVIM) diffusion MR and diffusion kurtosis imaging (DKI) in discriminating atypical bone metastasis from benign bone lesion in patients with tumors.Methods:Patients with bone lesions in lower extremity suspected of metastases were enrolled in this prospective study. IVIM diffusion MR and DKI were performed before biopsy. Apparent diffusion coefficient (ADC), true diffusion (D), perfusion fraction (f) and perfusion-related pseudodiffusion (D*) were generated with IVIM, while mean kurtosis (MK) and mean diffusion (MD) generated with DKI. Two radiologists blinded to pathology results separately measured these parameters for each lesion through drawing region of interest. Intraclass correlation coefficient was used to determine the inter-reader viability in measurement. The patients with pathology-confirmed metastasis or benign lesion were analyzed. The Mann–Whitney test was used to compare IVIM and DKI parameters between metastasis group and benign lesion group. Receiver operating characteristic curves were constructed to evaluate the ability of discrimination.Results:Bone lesions from 28 patients (metastasis, n = 15; benign lesion, n = 13; mean age = 55 years; age range, 34~77) were analyzed with IVIM and DKI. Intraclass correlation coefficient was greater than 0.8 for all parameters. ADC, D and MD were significantly lower in metastases versus benign lesions (p<0.05). MK and f value were significantly higher in metastases versus benign lesions (p<0.05). D* was not significantly different between the two groups (p>0.05). Areas under curve for ADC, D, f, MK and MD were 0.935, 0.939, 0.891, 0.840 and 0.844 respectively.Conclusions:IVIM and DKI derived parameters distinguish between atypical bone metastasis and benign bone lesion in selected patients with tumors.Advances in knowledge:Bone metastasis and benign bone lesion differ in water molecular diffusion.Intravoxel incoherent motion derived true diffusion distinguishes between atypical bone metastasis and benign lesion.

Radiolocalization of atypical lesions for intraoperative identification: technical factors, localization quality, success rates, patient safety, and spectrum of applications

BackgroundTo retrospectively analyze perilesional technetium Tc-99m MAA injection for intraoperative localization of atypical soft-tissue and bone lesions within a single tertiary referral center in order to determine technique, safety, and clinical utility of these procedures.MethodsAn IRB compliant, retrospective electronic chart review (2010–2017) exploring surgical excision of atypical (non-pulmonary, non-breast, non-sentinel node) lesions guided by Tc-99m MAA perilesional injection. Patient demographics, lesion location, lesion size, radiotracer injection technique, radiotracer injection complications, scintigraphy technique, scintigraphic quality, intraoperative time, lesion identification in surgery, and pathological diagnoses were recorded.ResultsTwenty-two atypical radiolocalization exams were identified. Lesion sites included rib (7), lymph node (4), abdominal wall (3), mesenteric (3), gallbladder fossa (1), retroperitoneum (1), parietal pleura (1), anterior mediastinum (1), and iliac bone (1). Average lesion size was 14 mm (range 5–23 mm). Eighteen (82%) radiotracer injections used computed tomography guidance and 4 (18%) used ultrasound guidance. The mean activity of Tc-99m MAA administered was 11.8 MBq (0.32 mCi). A 22-gauge needle was most often used for perilesional injection. No injection complications were reported. The lesions were identified with a hand-held gamma probe during surgery in 100% of cases. Of the samples sent to pathology, 100% were identified and given a diagnosis.ConclusionRadiolocalization of atypical lesions may be a valuable technique, guiding minimally invasive surgical removal of lesions that would otherwise be difficult to identify intraoperatively such as non-palpable rib, central mesenteric nodal, and abdominal wall lesions.

Clinical and Radiologic Manifestations of Cat-Scratch Osteomyelitis in Children

BackgroundOsteomyelitis (OM) is a rare sequela of cat scratch disease (CSD), often with atypical bone involvement. Clinical presentation of CSD OM is not well described. We sought to determine the clinical and radiologic manifestations of CSD OM patients admitted to Nationwide Children’s Hospital.MethodsEMR of inpatients was reviewed between January 2010 and March 2017. Clinical, radiological, and histopathological findings were collected.ResultsNine patients with positive cat scratch serology and/or tissue PCR were identified. Mean age was 6 years and 8 months (range 3–12 years). Patients had a prolonged course of illness before the diagnosis was made (mean 9.7 days). All patients had fever and affected bone area pain. Patients had normal WBC (mean 11,800/mm3) and modest ESR (mean 53.2 mm/hours) and CRP (mean 5.2 mg/dl) elevations on admission. Six patients had osteomyelitis at ≥ 2 sites (multifocal) with no contiguous lymphadenopathy (LAD). The vertebrae and pelvic girdle were the most common sites. Two patients had contiguous paraspinal abscesses, and 1 patient had a concomitant lymph node (LN) abscess. No osteolytic lesions were identified. Serology in all (9 of 9 IgG, 7 of 9 IgM) and PCR of bone in 2 of 2 patients were positive. All patients received antimicrobial therapy with median duration of 28 days (IQR 15–50).PatientLiver, spleen, LADVertebra/ spine/pelvisLong bonesOther bonesTreatmentTreatment before admission evaluation1Liver, Left axillary LADT7, S2, ischiumFemur, tibiaSkull base, 11th rib sternum,Rifampin (R), doxycycline (D)2Bilateral inguinal LADT3–5, T12, L1–2, S1, acetabulumR, DR, Azithromycin (A)3L2AA4Paraspinal and epidural abscess, inguinal LADT8, T11R, DA5Contiguous LAD with abscessHumerusTMP/SMX (T), RA6Left inguinal LAD, small liver and spleen lesionsT11, S1–4T, R, ciprofloxacin (C)C, R, A7Psoas muscle, paraspinal abscessL3, L5, S1, sacroiliitis4thribCT, R8NoT3A9NoIschiumFemurA, RConclusionCSD OM has an indolent course of illness with moderate elevation of inflammatory markers. Unlike previous reports of CSD and other bacterial OM, multifocal osteomyelitis without contiguous LN involvement was common. Despite significant variations in treatment duration and antimicrobial therapy choices, all patients had clinical resolution of their CSD-associated disease.Disclosures All authors: No reported disclosures.

(Pan-)cytopenia as first manifestation of kryptic telomeropathies in adults

Telomere syndromes (syn. Telomeropathies) are inherited disorders hallmarked by accelerated telomere shortening based on a molecular defect within the telomerase/telomere complex. The rare, but well-defined model disorder Dyskeratosis congenita (DKC) characterized by typical skin manifestations and bone marrow failure represents the classical manifestation of telomere syndromes in childhood and adolescence. However, cryptic variants of DKC, clinically manifest through appearance of atypical bone marrow failure, lung fibrosis or liver cirrhosis - especially in adults up to the fifth decade of age - are frequently underdiagnosed. Clinical awareness is of utmost importance for this group of patients considering the fundamental implications of this diagnosis for treatment decisions and surveillance. Here, we review the importance of screening, correct diagnosis and therapeutic implications of telomeropathies in adult patients with mostly cryptic DKC with particular focus on (pan-)cytopenia as first and most frequent clinical manifestation.

Monoclonal gammopathy-associated pure red cell aplasia.

Pure red cell aplasia (PRCA) is a rare disorder characterized by inhibition of erythroid precursors in the bone marrow and normochromic, normocytic anaemia with reticulocytopenia. Among 51 PRCA patients, we identified 12 (24%) patients having monoclonal gammopathy, monoclonal gammopathy of undetermined significance or smouldering multiple myeloma, with presence of monoclonal protein or abnormal serum free light chains and atypical bone marrow features of clonal plasmacytosis, hypercellularity and fibrosis. Thus far, three patients treated with anti-myeloma based therapeutics have responded with reticulocyte recovery and clinical transfusion independence, suggesting plasma cells play a key role in the pathogenesis of this specific monoclonal gammopathy-associated PRCA.

BONE HISTOLOGY OF PATIENTS WITH ALENDRONATE-MEDIATED FRACTURED BONE — A NEW ENTITY OF ATYPICAL OSTEOMALACIA

Based on the pharmaco-physiology of the aminobisphosphonates, it could be speculated that bisphosphonates could induce not only the osteopetrotic bone disease because of their selective suppression of osteoclastic activity, but also could affect directly or indirectly the endocrine system, local factors, and also the bone metabolic turnover. Consequently, the bone fragility could be rather produced by long-term aminobisphosphonate therapy. Bisphosphonate-mediated bone disease was labeled by Odvina et al. in 2005 [Odvina CV, Zerwerth JE, Rao DS et al. Severely suppressed bone turnover; a potential complication of alendronate therapy. J Clin Endocrinol Metab 90: 1294–1301, 2005.] as the "severely suppressed bone turnover (SSBT)" on the metabolic turnover basis. However, such definition could contain various drug-induced bone diseases, and did not indicate any particular condition, induced by the bisphosphonate. The term "SSBT" is thought not solely to be based on its histology, and seems rather a clinical term applicable to the various drug-induced bone diseases. Therefore, the current authors attempted to characterize the bisphosphonate-mediated bone disease on the basis of the combined image and histological studies, and finally concluded that the prolonged bisphosphonate therapy could produce an atypical osteomalacic bone disease. (osteosclerosis of osteomalacia) which leads to fragility fracture. It is puzzling as to why malacia rather than petrosis develops in the skeleton.

Unusual endosteally formed bone tissue in a patagonian basal sauropodomorph dinosaur.

Mussaurus patagonicus (Dinosauria: Sauropodomorpha) is a basal sauropodomorph from the Late Triassic of southern Argentina that is known from a large number of individuals, including juveniles, subadults, and adults. Here, we report on the occurrence of an unusual bone tissue in an individual of M. patagonicus. The rather atypical bone tissue is located within the femoral medullary cavity and also occurs within several erosion cavities of the midinner part of the cortex. This tissue is well vascularized and is composed of a matrix that consists of abundant and densely packed osteocyte lacunae. Although some features of this tissue resembles avian medullary bone, the histological features are distinctive and share more features with the pathological, reactive bone produced in extant birds in response to a retrovirus-induced disease (avian osteopetrosis). Here, we also discuss and provide histological features to effectively differentiate endosteally formed medullary bone from pathological avian osteopetrosis.

Alendronate-induced atypical bone fracture: evidence that the drug inhibits osteogenesis

Alendronate (ALN) is used for the treatment of post-menopausal osteoporosis. By reducing bone turnover, it increases bone mineral density. However, recent reports suggest an increased risk of atypical bone fractures after long-term ALN administration. Despite its well-known anti-osteoclastic activity, it is unclear whether ALN also suppresses human mesenchymal stem cell (hMSC)-mediated osteogenesis, thus possibly resulting in atypical bone fragility. We hypothesized that ALN does this and we look at its in vitro effects on osteogenesis. Morphological analysis, reverse transcriptase polymerase chain reaction, cell viability, alkaline phosphatase (ALP) activity and mineralization assays were investigated in hMSCs treated with a wide range of ALN. After treatment with high concentrations of ALN for 3 and 7days, cell viability was significantly reduced and cell morphology was altered. Osteogenic differentiation of hMSCs was also substantially suppressed as demonstrated by decreased ALP activity although ALN did not affect osteogenic-related genes tested. Furthermore, ALN at all concentrations tested drastically inhibited alizarin red S-positive mineralized matrix. ALN has a strong inhibitory effect on hMSC-mediated osteogenesis by suppressing cell proliferation, osteoblast differentiation and function. The insight gained may help in the development of safer alternatives.