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Osteopoikilosis and ankylosing spondylitis: Strange bedfellows: A case report

2019; Wiley; Volume: 22; Issue: 6 Linguagem: Inglês

10.1111/1756-185x.13594

1756-185X

Rachel O. Joseph, Joe Thomas, Padmanabha Shenoy,

Heterotopic Ossification and Related Conditions

International Journal of Rheumatic DiseasesVolume 22, Issue 6 p. 1162-1164 CORRESPONDENCEFree Access Osteopoikilosis and ankylosing spondylitis: Strange bedfellows: A case report Rachel O. Joseph, Corresponding Author Rachel O. Joseph [email protected] orcid.org/0000-0001-5471-9836 Dr. Shenoy's CARE, Kochi, India Correspondence Rachel O. Joseph, Dr. Shenoy's CARE, Opposite Chevrolet Show Room, Near Toyota Show Room NH-47, Nettoor, Cochin - 682040, India. Email: [email protected]Search for more papers by this authorJoe Thomas, Joe Thomas orcid.org/0000-0001-7255-6356 Aster Centre of Excellence in Orthopaedics & Rheumatology, Aster Medcity, Kochi, IndiaSearch for more papers by this authorPadmanabha Shenoy, Padmanabha Shenoy orcid.org/0000-0002-7666-1361 Dr. Shenoy's CARE, Kochi, IndiaSearch for more papers by this author Rachel O. Joseph, Corresponding Author Rachel O. Joseph [email protected] orcid.org/0000-0001-5471-9836 Dr. Shenoy's CARE, Kochi, India Correspondence Rachel O. Joseph, Dr. Shenoy's CARE, Opposite Chevrolet Show Room, Near Toyota Show Room NH-47, Nettoor, Cochin - 682040, India. Email: [email protected]Search for more papers by this authorJoe Thomas, Joe Thomas orcid.org/0000-0001-7255-6356 Aster Centre of Excellence in Orthopaedics & Rheumatology, Aster Medcity, Kochi, IndiaSearch for more papers by this authorPadmanabha Shenoy, Padmanabha Shenoy orcid.org/0000-0002-7666-1361 Dr. Shenoy's CARE, Kochi, IndiaSearch for more papers by this author First published: 14 May 2019 https://doi.org/10.1111/1756-185X.13594Citations: 1AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL 1 INTRODUCTION Osteopoikilosis (OPK) is a benign, rare, autosomal-dominant sclerosing bony dysplasia characterized by focal deposits of dense lamellar bone in the spongiosa.1 It mainly affects small tubular bones of hands and feet, the meta-epiphyseal region of long bones and pelvis; the appendicular skeleton is usually spared.2 It may mimic other bone pathologies such as bone tumors like osteosarcoma or be associated with rheumatic diseases like ankylosing spondylitis (AS), fibromyalgia, psoriatic arthritis and familial Mediterranean fever.3, 4 OPK is usually asymptomatic and is typically an incidental finding on imaging studies for unrelated conditions. Normal laboratory findings, bone scintigraphy or magnetic resonance imaging (MRI) may be necessary to rule out other pathologies.5 Radiologically OPK lesions appear as round, oval or linear hyperdense opacities ranging in size from 2 to 10 mm. The lesion number in a single bone ranges from a few to hundreds. It tends to increase with age and the largest lesions are located in the pelvis.2 In clinical and radiological follow-up of OPK, the lesions remain stable. AS, a spondyloarthropathy, is a chronic inflammatory disorder affecting primarily the sacroiliac joint and the axial skeleton. The etiology of AS is not clearly understood; however, a strong genetic predisposition exists. It shows a strong association with human leukocyte antigen (HLA)-B27. We present a rare case of OPK coexisting with AS. 2 CASE REPORT A 19-year-old girl with a strong family history of AS was admitted to the rheumatology ward with 2 years history of inflammatory back pain with early morning stiffness of around 3 hours which was aggravated over the previous month. She also gave a history of bilateral heel pain and pain at the costochondral junction on taking a breath, with temporary relief of symptoms on taking nonsteroidal anti-inflammatory drugs (NSAIDS). On physical examination, there was tenderness elicited at the sacroiliac (SI) joints, FABERS (flexion, abduction and external rotation) test was positive along with tenderness of bilateral Achilles tendon insertion, painful limitation of movement of the lumbar spine—modified Schober's test 3 cm. Her blood counts were normal with an elevated C-reactive protein, erythrocyte sedimentation rate and HLAB27 negativity. Radiograph of the pelvis showed multiple, small, well-defined ovoid areas of bony sclerosis scattered in the pelvis and head of the femur with bilateral sacroiliitis grade 2 (Figure 1). Bone scan showed increased activity suggesting inflammation on both sacroiliac joints but there was no osteoblastic activity. MRI of the SI joint showed evidence of active bilateral sacroiliitis (Figure 2). Her father's pelvic X-ray was also taken which did not show any evidence of OPK but had Grade 4 sacroiliitis. A diagnosis of OPK with coexistent AS was made based on the diagnostic lesions on radiographs and fulfilment of the New York criteria for AS. She was initiated on NSAIDS and sulphasalazine. After 3 months there was no improvement in her complaints and she had an active disease with a Bath AS Disease Activity Index of 5. Hence, infliximab was initiated and remains on follow-up. Figure 1Open in figure viewerPowerPoint Anteroposterior radiograph of the pelvis showing small oval or round sclerotic foci in both proximal femur and in the iliac bone predominantly in regions adjacent to sacroiliac and hip joints with bilateral grade 2 sacroiliitis Figure 2Open in figure viewerPowerPoint Short T1 inversion recovery sequence showing signs of disease activity in the form of edema in the bone marrow 3 DISCUSSION Osteopoikilosis or osteopathia condensans disseminated or spotted bones, first described in 1915 by Albers-Schonberg, is a rare, benign osteosclerotic dysplasia of unknown origin which is characterized by defective endochondral bone maturation processes. Its prevalence is estimated at 1/50 000, is seen in both men and women at any age, which persists throughout life. It is an inherited autosomal disorder although sporadic cases do exist, as in our patient. Studies indicate a loss-of-function mutation in the LEMD3 gene with various other hypotheses.6 It is a benign condition, typically asymptomatic; however it can mimic other bone diseases or be associated with other rheumatic diseases. Our patient had inflammatory back pain, plantar fasciitis, positive FABERS test with sacroiliitis on imaging along with typical benign OPK lesions. There are a number of differential diagnoses, the major one being osteoblastic metastases (Table 1). Table 1. Differential diagnosis for osteopoikilosis Sclerotic bone metastasis (especially from prostrate carcinoma) Osteopathia striata Osteoporosis Melorheostosis Tuberous sclerosis Paget's disease Hyperparathyroidism Mastocytosis Enostosis Osteoma These metastatic lesions are asymmetrical and have a predilection for axial skeleton involvement7 (Table 2). Mungovan et al suggested that in a setting of characteristic radiologic findings of OPK an abnormal bone scan does not exclude its diagnosis.8 Table 2. Differentiating features of OPK from metastatic osteoblastic lesions Osteopoikilosis Metastatic osteoblastic lesion Distribution Symmetrical Asymmetrical Site Predilection for metaphysic and epiphysis of long bones Predilection for axial skeleton Uniformity Uniform lesions, numerous oval to round lesions between 2 and 10 mm without osseous destruction Ill-defined lesions with osseous destruction Bone scan Typically no increased uptake of radioactive tracer Numerous hotspots of increased activity Magnetic resonance imaging Hypointense signal in T1 and T2 sections Focal or diffuse areas of hypointensity on T1 images and areas of intermediate or high signal intensity on T2 images. It appears hyperintense on short T1 inversion recovery images Inflammatory back pain is the most important symptom of spondyloarthritis (SpA). However, other causes like malignancies, infections and epidural abscess need to be ruled out. AS is the prototype of axial SpA characterized by presence of spinal pain, resulting in limitation of spinal mobility and radiological evidence of structural changes in the sacroiliac joints and spine. Since AS usually starts in early adulthood, the lifetime impact of the disease can be considerable, resulting in stiffness, fatigue, limitation of social activities and participation if left untreated. NSAIDs, tumor necrosis factor (TNF) blockers are the only effective drugs for treatment of AS. On the other hand, OPK does not require any treatment but only follow-up to survey other conditions which may require treatment and the potential risk of malignant transformation. Put together, the history, clinical and radiological findings in our patient, a diagnosis of OPK coexisting with AS was made and she has been initiated on anti-TNF therapy (infliximab). This association between OPK and AS is rarely reported. Ismail Sari et al reported a case of OPK coexistent with AS and FMF.4 Ozghur Akgul et al in a letter to the editor, reported a case of "OPK and AS: a rare coexistence and good response to TNF blocker adalimumab." They also mentioned there was no change in OPK on pelvis radiograph after anti-TNF therapy.9 To conclude, although OPK is an asymptomatic, benign and rare disease it can be confusing in patients with abnormal symptoms or tests. A detailed history, radiographs, bone scan, MRI should be taken to confirm the diagnosis and rule out coexistent conditions. Affected patients with OPK live normally without any treatment. However, other conditions associated with OPK may require treatment and regular follow-up. REFERENCES 1Boulet C, Madani H, Lenchik L, et al. Sclerosing bone dysplasias: genetic, clinical and radiology update of hereditary and non-hereditary disorders. Br J Radiol. 2016; 89: 20150349. 2Benli IT, Akalin S, Boysan E, et al. Epidemeological, clinical and radiological aspects of osteopoikilosis. J Bone Joint Surg Br. 1992; 74: 502. 3Mindell ER, Northup CS, Douglass HO Jr. Osteosarcoma associated with osteopoikilosis. J Bone Joint Surg Am. 1978; 60: 406- 408. 4Sari I, Simsek I, Guvenc T, et al. Osteopoikilosis co-existent with ankylosing spondylitis and familial mediterrnean fever. Rheumatol Int. 2009; 29: 321- 323. 5Yan Hul W, Vanhoenacker F, Balemans W, et al. Molecular and radiological diagnosis of sclerosing bone dysplasias. Eur J Radiol. 2001; 40: 198- 207. 6Woyciechowsky TG, Monticielo MR, Keiserman B, et al. Osteopoikilosis: what does the rheumatologist must know about it? Clin Rheumatol. 2012; 31: 745- 748. 7Bal S, Turan Y, Deniz G, Gurgan A. Osteopoikilosis patient with abnormal bone scan. Turk J Phys Med Rehabil. 2008; 54: 69- 72. 8Mungovan JA, Tung GA, Lambiase RE, Noto RB, Davis RP. Tc-99m MDP uptake in osteopoikilosis. Clin Nucl Med. 1994; 19(1): 6- 8. 9Ozgur A, Isa C, Emre E, et al. Osteopoikilosis and ankylosing spondylitis: a rare co-existence and good response of TNF blocker and adalimumab. Int J Rheumat Dis. 2015; 18(3): 372- 374. Citing Literature Volume22, Issue6June 2019Pages 1162-1164 FiguresReferencesRelatedInformation