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Bizarre parosteal osteochondromatous proliferation on a phalanx with periosteal erosion
Formosan Journal of Surgery (2016) 49, 31e34
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.e-fjs.com
CASE REPORT
Bizarre parosteal osteochondromatous proliferation on a phalanx with periosteal erosion Chi-Yu Wang a,b, Yu-Jen Shih a, Chang-Yi Chou a, Chih-Hsin Wang a,*, Chun-Kai Chang a, Tim-Mo Chen a, Shyi-Gen Chen a, Zheng-Yi Huang c a Division of Plastic Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan b Division of Plastic Surgery, Department of Surgery, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan c Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
Received 10 September 2014; received in revised form 6 October 2014; accepted 29 July 2015
Available online 15 January 2016
KEYWORDS bizarre parosteal osteochondromatous proliferation; phalanx tumor; BPOP; Nora’s lesion
Summary Bizarre parosteal osteochondromatous proliferation (BPOP) is an uncommon benign hand tumor with a high rate of local recurrence, marked proliferative activity, and an atypical histological appearance. The aim of this paper is to present a rare and illustrative example of BPOP with periosteal erosion. A 64-year-old male presented with a 10-year history of a mass, measuring approximately 3 cm in diameter, on the dorsal aspect of the right index finger. On physical examination, the mass was hard, indolent, and located at the level of the proximal phalanx. Roentgenograms displayed a soft tissue mass over the right index finger with erosion of the periosteum. Magnetic resonance imaging revealed a few well-defined lobulated tumors over the right index finger proximal interphalangeal joint with periosteal reaction. The soft tissue tumors were excised and found to have soft consistencies. Pathological findings demonstrated that the tumor was compatible with BPOP. BPOP is a benign but locally aggressive fibro-osseous mass yielding radiographic findings that bear striking clinical similarities to
Conflicts of interest: None. * Corresponding author. Plastic and Reconstructive Surgery, Tri-Service General Hospital, National Defense Medical Center, Number 325, Cheng-Kung Road, Section 2, Neihu 114, Taipei, Taiwan. E-mail address: [email protected] (C.-H. Wang). http://dx.doi.org/10.1016/j.fjs.2015.07.006 1682-606X/Copyright ª 2016, Taiwan Surgical Association. Published by Elsevier Taiwan LLC. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
32
C.-Y. Wang et al. those of other diseases, such as osteochondroma, osteosarcoma, and myositis ossificans. As the radiographic findings of BPOP are equivocal, the differential diagnosis must be based on the pathological results. With this case report, we aim to inform physicians that a hand tumor with an aggressive clinical picture may be benign in origin. Copyright ª 2016, Taiwan Surgical Association. Published by Elsevier Taiwan LLC. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
1. Introduction Bizarre parosteal osteochondromatous proliferation (BPOP) is an uncommon benign tumor that usually presents as a bony swelling on the surface of a bone. It has a notably high rate of local recurrence (20e55%), marked proliferative activity, and an atypical histological appearance. BPOP is also called “Nora’s lesion,”1 which was named after the pathologist who first discovered it at the Mayo Clinic in 1983. Nora et al1 reported 35 lesions found on a 50-year-old male patient, all involving the small bones of the hands and feet. In 1993, Meneses et al2 reported 65 cases of BPOP involving various sites, such as the hands, feet, long bones, and skull bones.
2. Case report A 64-year-old man presented with a 10-year history of an irregular mass, measuring approximately 3 cm in diameter, on the dorsal aspect of the right index finger (Figure 1). He claimed to have no history of trauma. On examination, the mass was hard, indolent, and located at the level of the proximal phalanx. Movement of the interphalangeal joint was mildly restricted. Results of neurovascular examination were unremarkable, and all laboratory investigations were within normal limits. Roentgenograms revealed a soft tissue mass with faint calcification over the right index finger base, and the adjacent proximal phalanx displayed irregular erosion of the periosteum (Figure 2). Through magnetic resonance imaging, a few well-defined lobulated tumors were noted over the medial and lateral aspects of the proximal interphalangeal joint of the right index finger, along with bony erosion and periosteal reaction. The
largest of these tumors was approximately 3 2 2 cm3. The tumors appeared isointense to muscle on T1-weighted images (Figure 3A) and heterogeneously hyperintense on T2-weighted images. They exhibited heterogeneous contrast enhancement with gadolinium injection (Figure 3B). Excision of the soft tissue tumors was performed using a dorsal longitudinal approach. The lobulated tumors were attached to the middle and proximal phalanges, and resected smoothly. Gross examination revealed a few lobulated tumors with soft consistencies and a maximum size of approximately 3 2 2 cm3. The extensor tendon was intact, and an irregular cortical surface was noted near the proximal interphalangeal joint (Figure 4). Pathological findings revealed irregular maturation of cartilage mixed with chondro-osteoid material, which had a bluish appearance in hematoxylin and eosin stain. Furthermore, numerous bizarre, binucleated chondrocytes were observed in the soft tissue. The tumor was compatible with BPOP (Figure 5).
3. Discussion BPOP is a rare, reactive, mineralizing mesenchymal lesion that typically affects the surfaces of bones in the hands and feet, typically the proximal and middle phalanges as well as the metacarpal and metatarsal bones.3 The hands are affected four times more than the feet. The typical clinical presentation is a painless swelling that grows for months to years.4 Pain or skin rubor can be caused by the mass effect.4,5 In typical radiological imaging, BPOP presents as a wellmarginated, ossified mass arising from the cortical surface.6 In general, the cortex is completely intact.6,7
Figure 1 Preoperative pictures display an irregular mass measuring approximately 3 cm in diameter on the dorsal aspect of the right index finger.
Bizarre parosteal osteochondromatous proliferation
33
Figure 2 X-ray images reveal a soft tissue mass with faint calcification over the index finger base (white arrows), and the adjacent proximal phalanx displays irregular erosion of the periosteum.
Figure 3 (A) Lesions appear isointense to muscle on the T1weighted image. (B) Lesions appear heterogeneously hyperintense to muscle in the T2-weighted image. A few well-defined lobulated tumors are present (maximum size: 3 2 2 cm3; white arrow) over the medial and lateral aspect of the proximal interphalangeal joint of the right index finger. Bony erosion and periosteal reaction are also evident (white circle).
Periosteal reaction and medullary involvement are typically absent in BPOP, which is associated with normal underlying bone and adjacent soft tissues.4,6,8,9 However, BarreraOchoa et al10 reported two atypical cases in 2012, each of which displayed the unusual radiographic feature of cortical destruction, which we also observed in the present case.11 Additionally, in 2007, Rybak et al5 reported four cases of BPOP with radiographic evidence of medullary involvement. Thus, the presence of equivocal findings might cause diagnostic dilemmas regarding BPOP during radiological investigations. Radiology is not a reliable method for identifying or excluding BPOP. Pathologically, BPOP has an atypical histological appearance, explaining the inclusion of the word “bizarre” in its name. Typical microscopic findings of BPOP include highly cellular, disorganized, and irregular cartilage, which is associated with the proliferation of bizarre-appearing fibroblasts, disorganized bone and spindle-shaped fibroblasts in the intertrabecular space, and bizarre binucleated chondrocytes of soft tissue.4,12 The bluish staining of the calcified cartilage matrix is a distinctive feature that has been interpreted as “blue bone.” Clinically, BPOP presents with bony exostosis and demonstrates a fairly high recurrence rate of 29e55% within a 2year interval.1,2 In the initial report by Nora et al,1 18 of 35 cases (51%) recurred. Meneses et al2 and Dhondt et al13 reported recurrence rates of 55% and 29%, respectively. Surgical removal should be planned with close follow-up because of this high rate of recurrence after local resection. Although the benign lesion in the present case is prone to recurrence, aggressive management with a mutilating surgery might be avoided for this benign lesion. In conclusion, BPOP is typically a well-defined mass that arises from the periosteal aspect of an intact cortex without medullary changes.13 However, atypical cases have also been reported, including the unusual radiographic feature of cortical destruction, which was observed in the present case. As the presence of equivocal radiological findings might cause diagnostic dilemmas regarding BPOP, radiological investigation is not a reliable method for identifying or excluding BPOP. Relying on pathological
34
C.-Y. Wang et al.
Figure 4 The few lobulated tumors have soft consistencies and a maximal size of approximately 3 2 2 cm3 (white arrow). The extensor tendon is intact, and an irregular cortical surface is noted near the proximal interphalangeal joint (black arrow).
Figure 5 Pathological findings reveal irregular maturation of cartilage mixed with chondro-osteoid material and a bluish appearance (black arrows), with numerous bizarre, binucleated chondrocytes in the soft tissue (hematoxylin and eosin stain, original magnification: 40).
findings is still necessary for the correct differential diagnosis of this disease.
Source(s) of support None.
References 1. Nora FE, Dahlin DC, Beabout JW. Bizarre parosteal osteochondromatous proliferations of the hands and feet. Am J Surg Pathol. 1983;7:245e250.
2. Meneses MF, Unni KK, Swee RG. Bizarre parosteal osteochondromatous proliferation of bone (Nora’s lesion). Am J Surg Pathol. 1993;17:691e697. 3. Orui H, Ishikawa A, Tsuchiya T, Ogino T. Magnetic resonance imaging characteristics of bizarre parosteal osteochondromatous proliferation of the hand: a case report. J Hand Surg Am. 2002;27:1104e1108. 4. Horiguchi H, Sakane M, Matsui M, Wadano Y. Bizarre parosteal osteochondromatous proliferation (Nora’s lesion) of the foot. Pathol Int. 2001;51:816e823. 5. Rybak LD, Abramovici L, Kenan S, Posner MA, Bonar F, Steiner GC. Cortico-medullary continuity in bizarre parosteal osteochondromatous proliferation mimicking osteochondroma on imaging. Skeletal Radiol. 2007;36:829e834. 6. Kenan S, Abdelwahab IF, Klein MJ, Hermann G, Lewis MM. Lesions of juxtacortical origin (surface lesions of bone). Skeletal Radiol. 1993;22:337e357. 7. Michelsen H, Abramovici L, Steiner G, Posner MA. Bizarre parosteal osteochondromatous proliferation (Nora’s lesion) in the hand. J Hand Surg Am. 2004;29:520e525. 8. Ly JQ, Bui-Mansfield LT, Taylor DC. Radiologic demonstration of temporal development of bizarre parosteal osteochondromatous proliferation. Clin Imaging. 2004;28:216e218. 9. Soon JL, Chang HC, Sim CS, Teoh LC, Low CO. A case of bizarre parosteal osteochondromatous proliferation of the hand. Singapore Med J. 2003;44:27e30. 10. Barrera-Ochoa S, Lluch A, Gargallo-Margarit A, Pe ´rez M, Ve ´lez R. Bizarre parosteal osteochondromatous proliferation (Nora’s lesion) of the hand: a report of two atypical cases. Case Rep Med. 2012;2012:453560. http://dx.doi.org/10.1155/2012/453560. 11. Nobusawa A, Sano T, Negishi A, Yokoo S, Yamaguchi T, Oyama T. Bizarre parosteal osteochondromatous proliferation of the maxilla: a case report. Oral Surg Oral Med Oral Pathol Oral Radiol. 2012;114:e20ee24. 12. De Smet L, Lambert I, Sciot R. Bizarre parosteal osteochondromatous proliferation of the hand: report of two cases. Chir Main. 2001;20:247e250. 13. Dhondt E, Oudenhoven L, Khan S, et al. Nora’s lesion: a distinct radiological entity? Skeletal Radiol. 2006;35:497e502.
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.e-fjs.com
CASE REPORT
Bizarre parosteal osteochondromatous proliferation on a phalanx with periosteal erosion Chi-Yu Wang a,b, Yu-Jen Shih a, Chang-Yi Chou a, Chih-Hsin Wang a,*, Chun-Kai Chang a, Tim-Mo Chen a, Shyi-Gen Chen a, Zheng-Yi Huang c a Division of Plastic Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan b Division of Plastic Surgery, Department of Surgery, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan c Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
Received 10 September 2014; received in revised form 6 October 2014; accepted 29 July 2015
Available online 15 January 2016
KEYWORDS bizarre parosteal osteochondromatous proliferation; phalanx tumor; BPOP; Nora’s lesion
Summary Bizarre parosteal osteochondromatous proliferation (BPOP) is an uncommon benign hand tumor with a high rate of local recurrence, marked proliferative activity, and an atypical histological appearance. The aim of this paper is to present a rare and illustrative example of BPOP with periosteal erosion. A 64-year-old male presented with a 10-year history of a mass, measuring approximately 3 cm in diameter, on the dorsal aspect of the right index finger. On physical examination, the mass was hard, indolent, and located at the level of the proximal phalanx. Roentgenograms displayed a soft tissue mass over the right index finger with erosion of the periosteum. Magnetic resonance imaging revealed a few well-defined lobulated tumors over the right index finger proximal interphalangeal joint with periosteal reaction. The soft tissue tumors were excised and found to have soft consistencies. Pathological findings demonstrated that the tumor was compatible with BPOP. BPOP is a benign but locally aggressive fibro-osseous mass yielding radiographic findings that bear striking clinical similarities to
Conflicts of interest: None. * Corresponding author. Plastic and Reconstructive Surgery, Tri-Service General Hospital, National Defense Medical Center, Number 325, Cheng-Kung Road, Section 2, Neihu 114, Taipei, Taiwan. E-mail address: [email protected] (C.-H. Wang). http://dx.doi.org/10.1016/j.fjs.2015.07.006 1682-606X/Copyright ª 2016, Taiwan Surgical Association. Published by Elsevier Taiwan LLC. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
32
C.-Y. Wang et al. those of other diseases, such as osteochondroma, osteosarcoma, and myositis ossificans. As the radiographic findings of BPOP are equivocal, the differential diagnosis must be based on the pathological results. With this case report, we aim to inform physicians that a hand tumor with an aggressive clinical picture may be benign in origin. Copyright ª 2016, Taiwan Surgical Association. Published by Elsevier Taiwan LLC. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
1. Introduction Bizarre parosteal osteochondromatous proliferation (BPOP) is an uncommon benign tumor that usually presents as a bony swelling on the surface of a bone. It has a notably high rate of local recurrence (20e55%), marked proliferative activity, and an atypical histological appearance. BPOP is also called “Nora’s lesion,”1 which was named after the pathologist who first discovered it at the Mayo Clinic in 1983. Nora et al1 reported 35 lesions found on a 50-year-old male patient, all involving the small bones of the hands and feet. In 1993, Meneses et al2 reported 65 cases of BPOP involving various sites, such as the hands, feet, long bones, and skull bones.
2. Case report A 64-year-old man presented with a 10-year history of an irregular mass, measuring approximately 3 cm in diameter, on the dorsal aspect of the right index finger (Figure 1). He claimed to have no history of trauma. On examination, the mass was hard, indolent, and located at the level of the proximal phalanx. Movement of the interphalangeal joint was mildly restricted. Results of neurovascular examination were unremarkable, and all laboratory investigations were within normal limits. Roentgenograms revealed a soft tissue mass with faint calcification over the right index finger base, and the adjacent proximal phalanx displayed irregular erosion of the periosteum (Figure 2). Through magnetic resonance imaging, a few well-defined lobulated tumors were noted over the medial and lateral aspects of the proximal interphalangeal joint of the right index finger, along with bony erosion and periosteal reaction. The
largest of these tumors was approximately 3 2 2 cm3. The tumors appeared isointense to muscle on T1-weighted images (Figure 3A) and heterogeneously hyperintense on T2-weighted images. They exhibited heterogeneous contrast enhancement with gadolinium injection (Figure 3B). Excision of the soft tissue tumors was performed using a dorsal longitudinal approach. The lobulated tumors were attached to the middle and proximal phalanges, and resected smoothly. Gross examination revealed a few lobulated tumors with soft consistencies and a maximum size of approximately 3 2 2 cm3. The extensor tendon was intact, and an irregular cortical surface was noted near the proximal interphalangeal joint (Figure 4). Pathological findings revealed irregular maturation of cartilage mixed with chondro-osteoid material, which had a bluish appearance in hematoxylin and eosin stain. Furthermore, numerous bizarre, binucleated chondrocytes were observed in the soft tissue. The tumor was compatible with BPOP (Figure 5).
3. Discussion BPOP is a rare, reactive, mineralizing mesenchymal lesion that typically affects the surfaces of bones in the hands and feet, typically the proximal and middle phalanges as well as the metacarpal and metatarsal bones.3 The hands are affected four times more than the feet. The typical clinical presentation is a painless swelling that grows for months to years.4 Pain or skin rubor can be caused by the mass effect.4,5 In typical radiological imaging, BPOP presents as a wellmarginated, ossified mass arising from the cortical surface.6 In general, the cortex is completely intact.6,7
Figure 1 Preoperative pictures display an irregular mass measuring approximately 3 cm in diameter on the dorsal aspect of the right index finger.
Bizarre parosteal osteochondromatous proliferation
33
Figure 2 X-ray images reveal a soft tissue mass with faint calcification over the index finger base (white arrows), and the adjacent proximal phalanx displays irregular erosion of the periosteum.
Figure 3 (A) Lesions appear isointense to muscle on the T1weighted image. (B) Lesions appear heterogeneously hyperintense to muscle in the T2-weighted image. A few well-defined lobulated tumors are present (maximum size: 3 2 2 cm3; white arrow) over the medial and lateral aspect of the proximal interphalangeal joint of the right index finger. Bony erosion and periosteal reaction are also evident (white circle).
Periosteal reaction and medullary involvement are typically absent in BPOP, which is associated with normal underlying bone and adjacent soft tissues.4,6,8,9 However, BarreraOchoa et al10 reported two atypical cases in 2012, each of which displayed the unusual radiographic feature of cortical destruction, which we also observed in the present case.11 Additionally, in 2007, Rybak et al5 reported four cases of BPOP with radiographic evidence of medullary involvement. Thus, the presence of equivocal findings might cause diagnostic dilemmas regarding BPOP during radiological investigations. Radiology is not a reliable method for identifying or excluding BPOP. Pathologically, BPOP has an atypical histological appearance, explaining the inclusion of the word “bizarre” in its name. Typical microscopic findings of BPOP include highly cellular, disorganized, and irregular cartilage, which is associated with the proliferation of bizarre-appearing fibroblasts, disorganized bone and spindle-shaped fibroblasts in the intertrabecular space, and bizarre binucleated chondrocytes of soft tissue.4,12 The bluish staining of the calcified cartilage matrix is a distinctive feature that has been interpreted as “blue bone.” Clinically, BPOP presents with bony exostosis and demonstrates a fairly high recurrence rate of 29e55% within a 2year interval.1,2 In the initial report by Nora et al,1 18 of 35 cases (51%) recurred. Meneses et al2 and Dhondt et al13 reported recurrence rates of 55% and 29%, respectively. Surgical removal should be planned with close follow-up because of this high rate of recurrence after local resection. Although the benign lesion in the present case is prone to recurrence, aggressive management with a mutilating surgery might be avoided for this benign lesion. In conclusion, BPOP is typically a well-defined mass that arises from the periosteal aspect of an intact cortex without medullary changes.13 However, atypical cases have also been reported, including the unusual radiographic feature of cortical destruction, which was observed in the present case. As the presence of equivocal radiological findings might cause diagnostic dilemmas regarding BPOP, radiological investigation is not a reliable method for identifying or excluding BPOP. Relying on pathological
34
C.-Y. Wang et al.
Figure 4 The few lobulated tumors have soft consistencies and a maximal size of approximately 3 2 2 cm3 (white arrow). The extensor tendon is intact, and an irregular cortical surface is noted near the proximal interphalangeal joint (black arrow).
Figure 5 Pathological findings reveal irregular maturation of cartilage mixed with chondro-osteoid material and a bluish appearance (black arrows), with numerous bizarre, binucleated chondrocytes in the soft tissue (hematoxylin and eosin stain, original magnification: 40).
findings is still necessary for the correct differential diagnosis of this disease.
Source(s) of support None.
References 1. Nora FE, Dahlin DC, Beabout JW. Bizarre parosteal osteochondromatous proliferations of the hands and feet. Am J Surg Pathol. 1983;7:245e250.
2. Meneses MF, Unni KK, Swee RG. Bizarre parosteal osteochondromatous proliferation of bone (Nora’s lesion). Am J Surg Pathol. 1993;17:691e697. 3. Orui H, Ishikawa A, Tsuchiya T, Ogino T. Magnetic resonance imaging characteristics of bizarre parosteal osteochondromatous proliferation of the hand: a case report. J Hand Surg Am. 2002;27:1104e1108. 4. Horiguchi H, Sakane M, Matsui M, Wadano Y. Bizarre parosteal osteochondromatous proliferation (Nora’s lesion) of the foot. Pathol Int. 2001;51:816e823. 5. Rybak LD, Abramovici L, Kenan S, Posner MA, Bonar F, Steiner GC. Cortico-medullary continuity in bizarre parosteal osteochondromatous proliferation mimicking osteochondroma on imaging. Skeletal Radiol. 2007;36:829e834. 6. Kenan S, Abdelwahab IF, Klein MJ, Hermann G, Lewis MM. Lesions of juxtacortical origin (surface lesions of bone). Skeletal Radiol. 1993;22:337e357. 7. Michelsen H, Abramovici L, Steiner G, Posner MA. Bizarre parosteal osteochondromatous proliferation (Nora’s lesion) in the hand. J Hand Surg Am. 2004;29:520e525. 8. Ly JQ, Bui-Mansfield LT, Taylor DC. Radiologic demonstration of temporal development of bizarre parosteal osteochondromatous proliferation. Clin Imaging. 2004;28:216e218. 9. Soon JL, Chang HC, Sim CS, Teoh LC, Low CO. A case of bizarre parosteal osteochondromatous proliferation of the hand. Singapore Med J. 2003;44:27e30. 10. Barrera-Ochoa S, Lluch A, Gargallo-Margarit A, Pe ´rez M, Ve ´lez R. Bizarre parosteal osteochondromatous proliferation (Nora’s lesion) of the hand: a report of two atypical cases. Case Rep Med. 2012;2012:453560. http://dx.doi.org/10.1155/2012/453560. 11. Nobusawa A, Sano T, Negishi A, Yokoo S, Yamaguchi T, Oyama T. Bizarre parosteal osteochondromatous proliferation of the maxilla: a case report. Oral Surg Oral Med Oral Pathol Oral Radiol. 2012;114:e20ee24. 12. De Smet L, Lambert I, Sciot R. Bizarre parosteal osteochondromatous proliferation of the hand: report of two cases. Chir Main. 2001;20:247e250. 13. Dhondt E, Oudenhoven L, Khan S, et al. Nora’s lesion: a distinct radiological entity? Skeletal Radiol. 2006;35:497e502.