Band Acro-Osteolysis as a Less Common Radiologic Pattern in Systemic Scleroderma: A Case Report

Introduction

Acro-osteolysis is a less common radiological finding characterized by the resorption or destruction of the distal phalanges of the hands or feet. ¹ It usually manifests as terminal tuft resorption, where the distal end of the phalanx is progressively eroded. However, transverse or band-like resorption, another form of manifestation which appears as a lytic band across the midshaft of the phalanx, is certainly less common than the terminal tuft pattern.^2,3 The clinical presentation of acro-osteolysis varies depending on the underlying etiology. Common symptoms include shortening of the digits, pain, and stiffness in the affected areas, particularly the distal interphalangeal joints. ⁴ Patients may also exhibit soft tissue changes such as atrophy, ulceration, or calcinosis, especially in systemic scleroderma. In cases associated with vascular insufficiency, such as Raynaud’s phenomenon, patients may report cold intolerance, color changes, or digital ischemia.^3,5 In pediatric populations or genetic syndromes, additional features like clubbing, joint hypermobility, or skin abnormalities may be present. ⁶

Acro-osteolysis arises from diverse etiologies, complicating diagnosis and underscoring the need for pattern-based differential assessment. Terminal tuft resorption is typically linked to systemic inflammatory diseases (such as systemic scleroderma and psoriatic arthritis), vasculopathies, metabolic disorders (eg, hyperparathyroidism), or thermal injuries. ⁷ In contrast, band acro-osteolysis is more frequently associated with genetic syndromes (like Hajdu-Cheney syndrome), environmental exposures (polyvinyl chloride), or idiopathic forms. ⁴ Single-digit involvement should prompt consideration of local pathology such as glomus tumors or epidermal inclusion cysts. ⁸

Herein, we report a case of systemic Scleroderma presenting with the rare finding of band acro-osteolysis and dactylitis in the absence of Raynaud’s phenomenon, and review the relevant literature.

Case Presentation

Clinical Examination

A 37-year-old female housekeeper presented to the rheumatology department with a 6-month history of progressive symptoms, including dactylitis, fingertip pain, swelling, and skin tightening affecting the upper limbs, face, and trunk (Figure 1A). She denied any history of Raynaud’s phenomenon, psoriasis, trauma, or exposure to polyvinyl chloride, and her family history was unremarkable for autoimmune or connective tissue diseases. Physical examination revealed prominent fingertip swelling and dactylitis in the absence of nail deformities. Skin tightening was evident over the upper limbs, face, and trunk, consistent with sclerodermatous changes. No other systemic abnormalities, such as cardiopulmonary or gastrointestinal involvement, were noted at presentation. Nailfold capillaroscopy revealed dilated capillary loops and avascular areas, consistent with scleroderma.

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Figure 1.

Clinical photograph showing skin tightening and dactylitis of the hands (A). Radiograph of the hands demonstrating midshaft bone resorption (band acro-osteolysis) in the first, second, and fifth digits bilaterally and the third digit of the left hand (B). Bone scan with 99mTc-MDP showing increased radiotracer uptake in the blood pool and skeletal phases in anterior (C and E respectively) and posterior (D and F respectively) views in the distal phalanges and distal interphalangeal joints, indicative of active inflammation.

Discussion

Systemic scleroderma, as observed in this case, is a complex autoimmune connective tissue disease characterized by vasculopathy, autoimmunity, and widespread fibrosis. ¹⁰ The presentation of dactylitis and band acro-osteolysis without Raynaud’s phenomenon is notably atypical, highlighting the heterogeneous nature of systemic scleroderma. Band acro-osteolysis, defined as transverse resorption across the midshaft of the distal phalanx, is a less common radiographic finding compared to terminal tuft resorption, mostly reported as a case report in the literature. Table 1 summarized the previous cases of band acro-osteolysis. Our study underscores the importance of recognizing atypical presentations to facilitate early diagnosis and intervention, particularly given the potential for severe complications such as digital ischemia or organ involvement in systemic scleroderma.

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Table 1.

Previous Case Reports on Band Acro-Osteolysis.

First author	Year	Title	Presentation
Zhang Z. 11	2024	Solitary Band Acro-osteolysis in Hajdu-Cheney Syndrome	An 11-y-old male presented with a shortened left thumb and lower back pain, exhibiting solitary band acro-osteolysis and distal phalangeal shortening of the left thumb.
Colquhoun M. 12	2021	Band acro-osteolysis in systemic sclerosis	A 63-y-old female with diffuse systemic scleroderma presented with finger swelling, no Raynaud’s phenomenon, and band acro-osteolysis in nine digits.
Teboul A. 13	2021	Papular mucinosis associated with band acro-osteolysis: a new syndrome associated with connective tissue-disease	A 44-y-old female with a history of progressively extensive papular and plaque skin lesions, associated with bilateral fingertips deformation and enlargement of the nail plates.
Uchiyama T. 4	2019	Band acro-osteolysis in a middle-aged woman	A 50-y-old female presented with fingertip pain, swelling, and mild clubbing of thumbs and index fingers. No Raynaud’s phenomenon was found. Band acro-osteolysis was observed on radiographs and MRI.
Tavare A. 2	2015	Band Acro-osteolysis	A 23-y-old male with a past history of autoimmune sclerosing cholangitis presented with a complaint of coldness in both hands, triphasic Raynaud’s phenomenon, and tightening of the skin.
Palav S. 14	2014	Hajdu-Cheney Syndrome: A case report with review of literature	A 43-y-old female patient presented to dental outpatient department with history of loose and premature loss of multiple teeth.

Analysis of the 6 reported cases along with our case of band acro-osteolysis revealed several key trends. Two out of 7 cases was Hajdu-Cheney Syndrome. The absence of Raynaud’s phenomenon, a common feature in systemic scleroderma, was noted in 4 of the 5 cases (^4,12,13, and our case), suggesting it may be less prevalent in band acro-osteolysis presentations (80% absence rate) compared to typical systemic scleroderma. Dactylitis, a prominent feature in our patient, contrasts with the soft tissue changes in other cases, where mucinosis (Teboul et al’s patient ¹³ ) or linear plaque of fibrosis (Tavare et al’s patient ² ) were seen in other cases, indicating variability in soft tissue involvement. The presence of anti-SSA antibody in our case and Teboul et al.’s patient, ¹³ an uncommon finding in systemic scleroderma, may suggest a unique subset or overlap syndrome. Differentiating our patient’s presentation from autoimmune overlap syndromes, such as mixed connective tissue disease (MCTD), is critical for accurate diagnosis. Unlike MCTD, which typically features Raynaud’s phenomenon, anti-U1-RNP positivity, and overlapping features of lupus, polymyositis, and systemic scleroderma, our patient lacked Raynaud’s and showed anti-SSA positivity. ¹⁵ The presence of band acro-osteolysis and dactylitis, absent in typical MCTD, further supports a distinct systemic scleroderma phenotype. Similarly, overlap with Sjögren’s syndrome is unlikely due to the absence of sicca symptoms, despite anti-SSA positivity. ¹⁶ This atypical immunological profile, combined with the rarity of band acro-osteolysis without Raynaud’s, underscores the diagnostic complexity and supports the need for personalized management strategies. ¹⁷

The pathogenesis of acro-osteolysis in systemic scleroderma is multifactorial, primarily involving vascular dysfunction and chronic inflammation. Digital ischemia, a hallmark of systemic scleroderma, promotes osteoclastogenesis through hypoxia-driven mechanisms, leading to bone resorption. Studies have shown a strong association between acro-osteolysis and severe digital ischemia, with up to 76% of patients with moderate to severe acro-osteolysis exhibiting significant vascular compromise. ¹⁸ The observed dactylitis and increased radiotracer uptake on the technetium-99m bone scan in the affected digits may reflect localized inflammation as a key driver of bone resorption.^3,18 Dactylitis, characterized by diffuse swelling of the digits, likely results from synovial and soft tissue inflammation, which could contribute to the mechanical stress and vascular changes promoting acro-osteolysis.^6,19 The heightened uptake on the bone scan, indicative of active bone turnover, suggests an inflammatory process involving osteoclast activity, potentially triggered by localized cytokine release or microvascular dysfunction, even in the absence of the systemic vasospasm typical of Raynaud’s.^20,21 This localized inflammation may thus represent an alternative pathogenic mechanism in our case, warranting further investigation into its role in band acro-osteolysis progression. Additionally, calcinosis, a frequent complication in systemic scleroderma, may exacerbate bone resorption, although the association requires further exploration. ⁵ The absence of Raynaud’s phenomenon in this patient suggests that other mechanisms, such as localized inflammation or autoantibody-mediated processes, may drive bone destruction. The presence of anti-SSA antibody raises the possibility of an overlap syndrome with Sjögren’s syndrome, though the lack of sicca symptoms makes this less likely. These antibodies are uncommon in systemic scleroderma but may indicate a unique immunological profile contributing to the atypical presentation. ²²

The absence of Raynaud’s phenomenon, a near-universal feature in systemic scleroderma (>95%), and the presence of anti-SSA antibodies challenge the vasculopathy model of acro-osteolysis. While digital ischemia from Raynaud’s phenomenon is strongly linked to terminal tuft resorption, ²³ our case demonstrates band acro-osteolysis driven by active inflammation in the absence of vasospasm. This is evidenced by dactylitis with ultrasound-confirmed synovitis, early-phase hyperemia on 99mTc-MDP bone scan (Figure 1C and D), and rapid bilateral progression within 6 months. These findings suggest localized cytokine-mediated osteoclast activation, potentially via IL-6, TNF-α, or RANKL pathways, independent of hypoxia.^24,25

Anti-SSA positivity, though rare in isolated systemic scleroderma (<5%), may reflect B-cell dysregulation or overlap autoimmunity. ¹⁶ Its presence in our patient, and 1 prior non-scleroderma band acro-osteolysis case, ¹³ raises the possibility of an immunologically distinct systemic scleroderma subset with enhanced inflammatory bone remodeling. This warrants future studies on anti-SSA as a biomarker for aggressive skeletal involvement in systemic scleroderma.

The etiology of acro-osteolysis is diverse, encompassing primary (genetic or idiopathic) and secondary (acquired) causes. Primary causes include hereditary syndromes such as Hajdu-Cheney syndrome, caused by mutations in the NOTCH2 gene, and primary hypertrophic osteoarthropathy (PHO), linked to mutations in HPGD or SLCO2A1 genes, which lead to elevated prostaglandin E2 levels and osteoclastic activity.^6,21,26 Secondary causes are more common and include systemic diseases like hyperparathyroidism, where excessive parathyroid hormone (PTH) activates osteoclasts, leading to subperiosteal bone resorption. This is more common in secondary or tertiary hyperparathyroidism associated with renal disease than in primary hyperparathyroidism. ²⁷ The patient’s normal PTH, calcium, and renal function exclude this possibility. Rheumatic diseases such as psoriatic arthritis may present with acro-osteolysis, but the absence of psoriasis or typical nail changes in this case makes this diagnosis unlikely. ⁶ Rare causes, such as leprosy or diabetic neuropathy, can induce acro-osteolysis through neuropathic mechanisms.^3,7 Other acquired causes include environmental exposures (eg, polyvinyl chloride), trauma, thermal injuries (frostbite or burns), and neuropathic conditions like leprosy or diabetic neuropathy.^8,28 Idiopathic non-familial acro-osteolysis is diagnosed when no underlying cause is identified. ⁴

Imaging plays a critical role in diagnosing and monitoring acro-osteolysis. Plain radiography remains the gold standard due to its ability to detect characteristic bone resorption patterns with high specificity. ²⁹ In our case, radiographs confirmed band acro-osteolysis, while the bone scan with 99mTc-MDP showed increased radiotracer uptake suggestive of active bone turnover, which may reflect inflammation, altered perfusion, calcific deposition, or reparative processes. ²⁰ Ultrasound findings confirmed the inflammation in this case. Advanced imaging modalities, such as computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound, are used for problem-solving or to assess soft tissue involvement. CT is particularly useful for detecting subtle bone changes or soft tissue calcifications, while dual-energy CT can differentiate uric acid deposits in gout-related cases. MRI excels in evaluating soft tissue masses, synovitis, or localized causes like tumors. Ultrasound can detect soft tissue abnormalities, such as synovitis or mineral deposition, and compares favorably to radiography in systemic scleroderma.^7,8 Single-photon emission computed tomography (SPECT/CT) combines functional and anatomical data, offering insights into active bone turnover and structural changes. ²⁰

Management of acro-osteolysis in systemic scleroderma focuses on addressing the underlying disease and preventing complications. ¹⁹ Immunosuppressive therapy, as initiated in this case with prednisolone and mycophenolate mofetil, targets inflammation and fibrosis. However, evidence suggests that acro-osteolysis may not reverse with treatment, emphasizing the need for early intervention to prevent progression. ²⁷ Vasodilators, such as calcium channel blockers or prostacyclin analogs, may be considered in patients with vascular involvement to mitigate ischemia-driven bone resorption, although they were not indicated in this case due to the absence of Raynaud’s phenomenon. ³⁰ Long-term follow-up is essential to monitor for complications such as pulmonary fibrosis or renal crisis, which are significant causes of morbidity in systemic scleroderma. ³¹ The atypical presentation in this case highlights the need for personalized treatment strategies and multidisciplinary care involving rheumatologists, radiologists, and dermatologists to optimize outcomes.^32,33

Conclusion

Band acro-osteolysis represents a rare and distinctive radiologic pattern in systemic scleroderma characterized by transverse mid-shaft resorption of the distal phalanges. This case demonstrates that band-type resorption can occur early and aggressively in the complete absence of Raynaud’s phenomenon, driven primarily by intense localized inflammation rather than chronic ischemia. The presence of dactylitis, anti-SSA positivity, and increased radiotracer uptake on bone scan highlights a unique inflammatory phenotype. Recognition of this atypical presentation enables early therapy, leading to rapid clinical improvement and prevention of irreversible digital damage.