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Intraosseous calcaneal lipoma
The Foot 13 (2003) 46–48
Case report
Intraosseous calcaneal lipoma D.W. Adams∗ , D.T. Smith Metrowest Medical Center, 115 Lincoln Street, Framingham, MA 01701, USA Received 27 August 2001; received in revised form 17 May 2002; accepted 29 May 2002
Abstract Intraosseous lipoma is a non-malignant bone tumor reported at increasing frequency. Diagnosis of these bone lesions can be made definitively using non-invasive modalities such as magnetic resonance imaging (MRI). We report this bone tumor as a possible etiology of chronic, plantar fascitis-type pain. A review of the literature is also presented. We describe a patient with an intraosseous calcaneal lipoma presenting as an unresolved case of plantar fascitis. Fat suppression images produced via MRI yielded definitive results. © 2003 Elsevier Science Ltd. All rights reserved. Keywords: Intraosseous calcaneal lipoma; Bone tumors; Heel pain
1. Background The prevalence of intraosseous lipomas was estimated at 1:1000 among bone tumors [1]. This rarity is mildly inaccurate due to the increase in published accounts following the widespread use of magnetic resonance imaging (MRI) following suspicious plain film analysis. Due to the relatively asymptomatic presentation of intraosseous lipomas, these anomalies are often incidental discoveries within routine examinations. The calcaneus represents the second most common site after proximal femur for lipomas within the bone [2]. Close examination of routine radiographs of the foot involves assessment of bone stock via calcaneal trabecular analysis as described by Jangi. During this examination of the trabeculation within the body of the calcaneus, osteolytic lesions are discovered within the neutral triangle (Fig. 1). Following plain film analysis, further characterization of unknown lytic lesions within the calcaneus must be pursued. The differential diagnosis for lytic lesions in the calcaneus includes both benign and malignant tumors as well as a few systemic disorders such as osteoporosis. Bone biopsy for positive identification of the lesion is ideal, but advances in both MRI and CT software allows identification of tumors without invasive procedures. Here we present one case of a patient presenting with heel pain unresolved by traditional plantar fascitis modalities with emphasis on clinical and radiologic signs. ∗ Corresponding
author. Tel.: +1-508-872-9288; fax: +1-508-620-7368. E-mail address: [email protected] (D.W. Adams).
Wehrsig described the first intraosseous lipoma in 1910; the tumor was located in the proximal fibula [3]. From a 1967 Mayo Clinic Study, Dahlin reported an incidence for intraosseous lipomas at one per thousand bone tumors seen [1]. Child reported the first calcaneal source of the tumor in 1955 [4]. The calcaneus has many attributes including potential medullary space and dense vascularity that could contribute to tumor growth. In addition, weight bearing provides a source of traumatic injuries that may mimic tumor-like conditions or vice versa. Most likely intraosseous lipomas are a benign neoplasm of the adipose tissue found in marrow cavities [5]. 2. Case report A 60-year-old female patient presented to the podiatrist’s office complaining of heel pain for 8 months. She had been using an anti-inflammatory medication for 1 month prior to visit. She also had been given two steroid injections by the previous caregiver. The patient states the first injection provided adequate relief, yet the second gave minimal pain relief. Prior to 1-month ago, the pain was mostly in the morning and after periods of prolonged rest. At this visit, the pain was described as unrelenting. Palpable, symmetrical pulses are detected. She has pain upon side to side compression of the calcaneus, but she has no pain with direct pressure of the plantar calcaneal tubercles. The patient has no pain with percussion along the course of the posterior tibial nerve. Radiographic examination reveals a radiolucent lesion located within the anterior
0958-2592/03/$ – see front matter © 2003 Elsevier Science Ltd. All rights reserved. PII: S 0 9 5 8 - 2 5 9 2 ( 0 2 ) 0 0 0 7 5 - 5
D.W. Adams, D.T. Smith / The Foot 13 (2003) 46–48
47
Fig. 1. Lateral radiograph demonstrating a focal well-demarcated lesion within the “neutral triangle” in the body of the calcaneus.
body of the calcaneus. Also, there is a smaller radiodense body identified within the bounds of the larger lesion. There is no cortical destruction and a well-defined transition between the lesion and the remaining calcaneal bone. No periosteal reaction or soft tissue swelling is noted (Fig. 2).
Differential diagnoses for benign bone lesions include osseous lipoma, osteoid osteoma, unicameral bone cyst, or aneurysmal bone cyst. Advanced imaging of the lesion at this point can aid in identifying this lesion. CT images typically provide good differentiation of lipomas from UBC’s, but if
Fig. 2. Sagittal T1 fat suppressed image demonstrating the homogenous lipomatous lesion.
48
D.W. Adams, D.T. Smith / The Foot 13 (2003) 46–48
Fig. 3. Sagittal T1 image demonstrates high signal intensities consistent with fatty lesions.
significant calcification occurs within the adipose tissue then the quality of the image decreases. Clinically, when evaluating MRI images of suspicious lesions, consider lipomas as the etiology if a high signal intensity is present on T1 images and no visible lesions on the fat-suppressed images (Fig. 3). Symptoms that last 8 months and are consistent with plantar fascitis can easily mislead anyone. Radiographic evaluation can create an entirely new differential and outlook on treatment. The absence of any pathologic fracture in the case presented leads one to treat the biomechanical strain and the lipoma becomes an incidental finding. Curretage with packing of the cancellous defect has not been proven to be effective without prior fracture. No metastases have been recorded to date of intraosseous lipomas. The patient was treated with an additional steroid injection and has been pain-free since.
3. Discussion Incidental findings on radiographs rarely arouse latent suspicions, but certain lesions when found require further evaluation. Magnetic resonance imaging software allows for accurate identification without surgery based on T1 and T2 weighted images, location, size, shape and effect of the tu-
mor on surrounding tissues [6]. Tumor histology appears as mature adipose tissue with intralesional calcifications. The advantages of MRI over open biopsy include decreased risk of infection, visualization of entire lesion in multiple planes, and anesthesia risks. The disadvantages are few including lack of specificity and absolute contraindications to MRI (claustrophobia, aneurysmal clips, metallic fragments in soft tissues). Most authorities agree surgical treatment is required of large, symptomatic lipomas in pathologic fractures of the calcaneus. We feel MRI is a needed step in the analysis of the non-malignant lesion, regardless of the treatment regimen. References [1] Dahlin D. Bone tumors. 2nd ed. Springfield, IL: Charles C Thomas; 1967. [2] Milgram JW. Intraosseous lipomas: a clinicopathologic study of 66 cases. Clin Orthop 1988;231:277. [3] Wehrsig G. Lipom des Knochenmarks. Zentralbl All Pathol 1976; 21:243, 1910. [4] Child P. Lipoma of the os calcis. Am J Clin Pathol 1955;23:1050. [5] Goldman AB, Marcove RC, Huovos AG, Smith J. Case report 280: intraosseous lipoma of the tibia. Skeletal Radiol 1984;12:209–12. [6] Cohen MD, Weetman RM, Provisor AJ, et al. Efficacy of magnetic resonance imaging in 139 children with tumors. Arch Surg 1986;121: 522.
Case report
Intraosseous calcaneal lipoma D.W. Adams∗ , D.T. Smith Metrowest Medical Center, 115 Lincoln Street, Framingham, MA 01701, USA Received 27 August 2001; received in revised form 17 May 2002; accepted 29 May 2002
Abstract Intraosseous lipoma is a non-malignant bone tumor reported at increasing frequency. Diagnosis of these bone lesions can be made definitively using non-invasive modalities such as magnetic resonance imaging (MRI). We report this bone tumor as a possible etiology of chronic, plantar fascitis-type pain. A review of the literature is also presented. We describe a patient with an intraosseous calcaneal lipoma presenting as an unresolved case of plantar fascitis. Fat suppression images produced via MRI yielded definitive results. © 2003 Elsevier Science Ltd. All rights reserved. Keywords: Intraosseous calcaneal lipoma; Bone tumors; Heel pain
1. Background The prevalence of intraosseous lipomas was estimated at 1:1000 among bone tumors [1]. This rarity is mildly inaccurate due to the increase in published accounts following the widespread use of magnetic resonance imaging (MRI) following suspicious plain film analysis. Due to the relatively asymptomatic presentation of intraosseous lipomas, these anomalies are often incidental discoveries within routine examinations. The calcaneus represents the second most common site after proximal femur for lipomas within the bone [2]. Close examination of routine radiographs of the foot involves assessment of bone stock via calcaneal trabecular analysis as described by Jangi. During this examination of the trabeculation within the body of the calcaneus, osteolytic lesions are discovered within the neutral triangle (Fig. 1). Following plain film analysis, further characterization of unknown lytic lesions within the calcaneus must be pursued. The differential diagnosis for lytic lesions in the calcaneus includes both benign and malignant tumors as well as a few systemic disorders such as osteoporosis. Bone biopsy for positive identification of the lesion is ideal, but advances in both MRI and CT software allows identification of tumors without invasive procedures. Here we present one case of a patient presenting with heel pain unresolved by traditional plantar fascitis modalities with emphasis on clinical and radiologic signs. ∗ Corresponding
author. Tel.: +1-508-872-9288; fax: +1-508-620-7368. E-mail address: [email protected] (D.W. Adams).
Wehrsig described the first intraosseous lipoma in 1910; the tumor was located in the proximal fibula [3]. From a 1967 Mayo Clinic Study, Dahlin reported an incidence for intraosseous lipomas at one per thousand bone tumors seen [1]. Child reported the first calcaneal source of the tumor in 1955 [4]. The calcaneus has many attributes including potential medullary space and dense vascularity that could contribute to tumor growth. In addition, weight bearing provides a source of traumatic injuries that may mimic tumor-like conditions or vice versa. Most likely intraosseous lipomas are a benign neoplasm of the adipose tissue found in marrow cavities [5]. 2. Case report A 60-year-old female patient presented to the podiatrist’s office complaining of heel pain for 8 months. She had been using an anti-inflammatory medication for 1 month prior to visit. She also had been given two steroid injections by the previous caregiver. The patient states the first injection provided adequate relief, yet the second gave minimal pain relief. Prior to 1-month ago, the pain was mostly in the morning and after periods of prolonged rest. At this visit, the pain was described as unrelenting. Palpable, symmetrical pulses are detected. She has pain upon side to side compression of the calcaneus, but she has no pain with direct pressure of the plantar calcaneal tubercles. The patient has no pain with percussion along the course of the posterior tibial nerve. Radiographic examination reveals a radiolucent lesion located within the anterior
0958-2592/03/$ – see front matter © 2003 Elsevier Science Ltd. All rights reserved. PII: S 0 9 5 8 - 2 5 9 2 ( 0 2 ) 0 0 0 7 5 - 5
D.W. Adams, D.T. Smith / The Foot 13 (2003) 46–48
47
Fig. 1. Lateral radiograph demonstrating a focal well-demarcated lesion within the “neutral triangle” in the body of the calcaneus.
body of the calcaneus. Also, there is a smaller radiodense body identified within the bounds of the larger lesion. There is no cortical destruction and a well-defined transition between the lesion and the remaining calcaneal bone. No periosteal reaction or soft tissue swelling is noted (Fig. 2).
Differential diagnoses for benign bone lesions include osseous lipoma, osteoid osteoma, unicameral bone cyst, or aneurysmal bone cyst. Advanced imaging of the lesion at this point can aid in identifying this lesion. CT images typically provide good differentiation of lipomas from UBC’s, but if
Fig. 2. Sagittal T1 fat suppressed image demonstrating the homogenous lipomatous lesion.
48
D.W. Adams, D.T. Smith / The Foot 13 (2003) 46–48
Fig. 3. Sagittal T1 image demonstrates high signal intensities consistent with fatty lesions.
significant calcification occurs within the adipose tissue then the quality of the image decreases. Clinically, when evaluating MRI images of suspicious lesions, consider lipomas as the etiology if a high signal intensity is present on T1 images and no visible lesions on the fat-suppressed images (Fig. 3). Symptoms that last 8 months and are consistent with plantar fascitis can easily mislead anyone. Radiographic evaluation can create an entirely new differential and outlook on treatment. The absence of any pathologic fracture in the case presented leads one to treat the biomechanical strain and the lipoma becomes an incidental finding. Curretage with packing of the cancellous defect has not been proven to be effective without prior fracture. No metastases have been recorded to date of intraosseous lipomas. The patient was treated with an additional steroid injection and has been pain-free since.
3. Discussion Incidental findings on radiographs rarely arouse latent suspicions, but certain lesions when found require further evaluation. Magnetic resonance imaging software allows for accurate identification without surgery based on T1 and T2 weighted images, location, size, shape and effect of the tu-
mor on surrounding tissues [6]. Tumor histology appears as mature adipose tissue with intralesional calcifications. The advantages of MRI over open biopsy include decreased risk of infection, visualization of entire lesion in multiple planes, and anesthesia risks. The disadvantages are few including lack of specificity and absolute contraindications to MRI (claustrophobia, aneurysmal clips, metallic fragments in soft tissues). Most authorities agree surgical treatment is required of large, symptomatic lipomas in pathologic fractures of the calcaneus. We feel MRI is a needed step in the analysis of the non-malignant lesion, regardless of the treatment regimen. References [1] Dahlin D. Bone tumors. 2nd ed. Springfield, IL: Charles C Thomas; 1967. [2] Milgram JW. Intraosseous lipomas: a clinicopathologic study of 66 cases. Clin Orthop 1988;231:277. [3] Wehrsig G. Lipom des Knochenmarks. Zentralbl All Pathol 1976; 21:243, 1910. [4] Child P. Lipoma of the os calcis. Am J Clin Pathol 1955;23:1050. [5] Goldman AB, Marcove RC, Huovos AG, Smith J. Case report 280: intraosseous lipoma of the tibia. Skeletal Radiol 1984;12:209–12. [6] Cohen MD, Weetman RM, Provisor AJ, et al. Efficacy of magnetic resonance imaging in 139 children with tumors. Arch Surg 1986;121: 522.