Adamantinoma of the Forearm: a Chronologic Presentation of a Slow-Growing Malignancy

Case Report

Adamantinoma of the Forearm: A Chronologic Presentation of a Slow-Growing Malignancy

Richard W. Gurich Jr, MD; Luminita Rezeanu, MD; and Scott E. Porter, MD, MBA, FACS

From the Department of Orthopaedic Surgery, Greenville Health System, Greenville, SC (R.W.G., S.E.P.), and Department of Pathology, Greenville Health System, Greenville, SC (L.R.)

Abstract The purpose of this report is to present a unique case of an uncommon tumor. Adamantinomas are inherently rare, low-grade malignant primary bone tumors that almost always involve the tibia. Although cases have been reported of these tumors involving the long bones of the upper extremity, we present an instance in which both bones of the forearm were affected with documented radiographic changes over a 7-year span. Surgical management is the mainstay of treatment for these tumors and usually requires limb reconstruction following resection. We also present an interesting reconstruction option for upper extremity limb salvage following surgical resection of these tumors.

damantinomas are slow-growing, low- meral joint using an allograft-prosthesis compos- grade malignant tumors usually found in ite. The aspects of this case—including its unique Athe long bones. These tumors were first location, histopathology, and reconstruction described in 1900. In 1913, Fischer coined the using a total elbow arthroplasty-allograft com- term “adamantinoma.”1 These tumors are uncom- posite—are discussed in the following sections. mon, representing less than 1% of all malignant bone tumors.2 They are characterized as affecting Case Description the tibia in 80%–90% of cases and usually occur A 60-year-old, right-handed woman was referred 3 in patients in the second and third decades of life. to our institution for evaluation of a right forearm Although adamantinomas show a predilection mass. Her medical history was significant for thy- for involvement of the tibia, other skeletal sites roid cancer in the remote past and a longstanding have been reported, including the femur, radius, radiographic diagnosis of fibrous dysplasia of the and ulna.4 Because of their malignant character- right ulna. At the time of presentation, her main istics, adamantinomas of the long bones are usu- complaint was an increase in right forearm pain ally treated with wide resection and reconstruc- and of swelling and progressive decrease in her tion. Surveillance for distant recurrence when functional range of motion. She had received no treating these tumors is mandatory as metastases other treatment beyond X-ray imaging before this are observed in 10%–30% of cases. presentation, and the progressive nature of the changes prompted referral (Figs. 1 and 2). Reports of involvement of the radius or ulna are limited to fewer than 10 cases, and we are Physical exam revealed asymmetry of her right unaware of any cases with simultaneous involve- proximal forearm as compared to the contra- ment of the radius and ulna. We report a unique lateral side. A palpable mass was observed that case of an upper extremity adamantinoma ulti- appeared to be nonmobile. The flex-extension mately affecting both the radius and ulna after a arc for elbow range of motion was observed to be long period of preoperative observation. Treat- 25 degrees of extension to 100 degrees in flexion, ment, therefore, included a wide resection of both 0 degrees of pronation, and 20 degrees of supi- the proximal radius and ulna and a subsequent nation. Neurovascular examination of the right reconstruction of the proximal ulna and ulnohu- upper extremity was unremarkable.

62 GHS Proc. June 2017; 2 (1): 62-66 ADAMANTINOMA OF THE FOREARM

Figure 1 Earliest available (7 years before referral) anteroposterior (A) and lateral (B) radiographs of the right forearm showing a lytic lesion of the A B proximal ulna.

Figure 2 Follow-up radiographs (24 months D before referral) are shown in (A) and (B), and X-rays obtained after referral A to our institution are shown in (C) and C (D); note the increased destruction of the ulna and involvement of the radius.

Earliest available radiographs of the right forearm were from an outside visit 6 years before Figure 3 her presentation (Fig. 1). When compared to Axial T1 fat suppressed with contrast (A) and coronal T2 fat suppressed current radiographs, the stark changes were (B) with magnetic resonance images from the patient’s right forearm. Both consistent with a very narrow differential radius and ulna are involved, and dimensions of the soft tissue mass are shown. diagnosis of adamantinoma, osteofibrous dysplasia, metastatic disease from her thyroid cancer history, or other primary malignancy of bone.

The severity of these diagnoses prompted magnetic resonance imaging (MRI) of the right forearm, a computer tomography (CT) scan of the thorax, and a whole-body nuclear medicine bone scan under the belief that the findings were suggestive of a malignancy. The CT scan of the thorax and bone scan were negative. The MRI of the right forearm, as seen in Figure 3, showed involvement of the ulna and radius with an extensive soft tissue A B mass. A CT-guided needle biopsy was then performed, and pathology was consistent with an adamantinoma of the radius and ulna with osteofibrous dysplasia-like areas.

GHS Proc. June 2017; 2 (1): 62-66 63 The patient was offered continued observation vs. Surgical Technique limb ablation vs. surgical intervention to include The surgical technique required a posterior inci- wide resection and reconstruction of the right sion that coursed from the distal third of the forearm. The patient elected to pursue limb sal- posterior humerus to the distal ulnar border of vage with wide resection of both the radius and the forearm. Given the extensive soft tissue mass, the ulna along with allograft prosthetic recon- a volar forearm incision was also used to access struction of the ulnohumeral joint. the radius and help provide visualization of the

Figure 4 Immediate postoperative anteroposterior (A) and lateral (B) forearm radiographs showing the total elbow arthroplasty-allograft composite. Sixteen- month follow-up lateral forearm (C), anteroposterior and oblique (D), and lateral elbow (E) radiographs show stable appearance of the A B allograft-prosthesis composite and a well- healed distal allograft- host bone junction.

C D

64 GHS Proc. June 2017; 2 (1): 62-66 ADAMANTINOMA OF THE FOREARM involved interosseous membrane and neurovas- Adamantinomas are slow-growing malignant cular structures. The mass was removed en bloc tumors with metastatic potential. Histologically, following soft-tissue dissection of it, osteotomies these tumors are typically biphasic, consisting of of both ulna and radius, and transection of the malignant epithelial cells juxtaposed against a triceps insertion on the proximal ulna. spindle cell stroma.5-7 The epithelial component of the tumor will stain positive for keratin. Planned reconstruction involved an allograft- prosthetic reconstruction. An allograft with Adamantinomas can be divided into classic and dimensions similar to the patient’s native bone differentiated (osteofibrous dyslasia-like) types. was obtained from the Musculoskeletal Trans- The difference resides in the amount of epithelial/ plant Foundation. The allograft was an entire neoplastic component present, which is abundant ulna with its soft tissue attachments. in the classic type and very sparse in the differentiated adamantinoma. The epithelial component A total elbow arthroplasty was cemented into is further subdivided into basaloid, squamoid, the patient’s native humerus and the ulna allograft. The triceps mechanism of the elbow was reconstructed by suturing the remaining native triceps to the allograft triceps remnant. Figure 5 The distal tendon of the biceps was sutured into Representative image from histologic analysis of the patient’s right forearm the remaining anterior soft tissues of the ulna mass biopsy. Note the biphasic histology composed of a fibrous stroma allograft. Distally, the ulnar allograft-host bone with cords of epithelial cells consistent with adamantinoma. junction was secured via compression plating with a plate and screw construct (Fig. 4). The wound was irrigated and closed, and the patient was placed in a long arm splint for 2 weeks.

Postoperative Course Clear surgical margins were obtained. Both gross and histologic examinations were performed by a musculoskeletal pathologist. Histologic section showed large multilobulated nests of adamantinoma composed of cords of epithelial-like cells in a myxoid stroma. In addition, osteofibrous dysplasia-like areas were present. Focal high- grade areas exhibiting more epithelioid features in cellularity were also identified (Fig. 5). Simple areas of fibrous dysplasia were not reported.

Postoperatively, the patient had pronation to 90 degrees, supination to neutral, and a 105-degree flexion-extension arc. The patient had allograft- host bone junction healing at 10 months. Fol- low-up at 16 months has shown no evidence of local recurrence or metastasis. Discussion This report outlines a unique case regarding an adamantinoma of the upper extremity involving both the ulna and radius. Although adamantinomas affecting the radius or ulna have been reported, we are unaware of any with simultaneous involvement of both bones of the forearm after such a long period of observation. Further, the total elbow allograft prosthetic composite secured with compression plating techniques presents an interesting method of reconstruction.

GHS Proc. June 2017; 2 (1): 62-66 65 Correspondence tubular, and spindle variants, according to its ture. Bourne et al reported on an adamantinoma Address to: histologic appearance. Also, some clinicians have involving the radius treated with en bloc excision Scott E. Porter, placed osteofibrous dysplasia and adamantinoma and reconstruction using a vascularized fibula MD, MBA, FACS, on a spectrum of disease, given some similarities graft.12 Keeney et al studied 85 cases of adaman- Greenville Health in their histological appearance.8 tinomas located in various anatomic locations System, 2nd Floor treated at their institution—only 2 involved the Support Tower, As mentioned above, these tumors are usually ulna and 1 the radius.3 Gianoutsos et al and Sher- 2,3 Department of found in the anterior cortex of the tibia. The man et al published reports of adamantinomas Orthopaedic Surgery, presentation of these tumors is analogous to the of the ulna, while Soucacos reported on a case 701 Grove Rd, presentation in this patient with pain, swelling, of an adamantinoma of the olecranon; this lat- 2 Greenville, SC 29605 and/or deformity. Secondary to the tumor’s ter case was unique for both its location and its ([email protected]) inherent malignant characteristics and insensi- subsequent bony metastases.13-15 However, none 9 tivity to chemotherapy or radiation, treatment of the above reports illustrated the chronolog- entails surgical management. En bloc resection ical progression of disease or the simultaneous followed by the appropriate reconstruction is the involvement of both bone of the forearm that our usual pathway for surgical treatment. case presents. Studies reporting patient survival are limited to Conclusion small patient numbers because of the rarity of the tumor. Published mortality rates related to Our case report illustrates a unique presentation adamantinomas, however, have been reported of an adamantinoma of the upper extremity. This to range from 13%–18%8; the rate of metastases case is not only unique for its areas of involve- ranges from 15%–30%.2,10 Additionally, local ment, but also its progression before and after recurrence of these tumors can occur 5–15 years referral to our institution. These tumors are tra- after diagnoses, mandating that these patients be ditionally slow-growing; however, our report was followed for an indefinite time.11 able to chronologically follow the progression of this particular patient’s malignancy, ultimately Adamantinomas isolated to either the radius or treated with en bloc resection and a unique ulna have been reported previously in the litera- reconstruction method. References 1. Rakhn LB. Adamantinoma, osteofibrous dysplasia 9. Hazelbag HM, Taminiau AH, Fleuren GJ, Hogen- and differentiated admantinoma. Skeletal Radiol. doorn PC. Adamantinonma of the long bones: A 2003;32:245-58. clinciopathological study of thirty two patients 2. Most MJ, Sim FH, Inwards CY. Osteofibrous dys- with emphasis on histological subtype, precursor lesion, and biological behavior. J Bone Joint Surg Am. plasia and adamantinoma. J Am Acad Orthop Surg. 1994;76:1482-99. 2010;18:358-66. 10. Quereshi AA, Shott S, Mallin BA, Gietlis S. Current 3. Keeney GL, Unni KK, Beabout JW, Pritchard DJ. trends in the management of adamantinoma of long Admantinoma of long bones: a clinicopathologic bones: an international study. J Bone Joint Surg Am. study of 85 cases. Cancer. 1989;64:730-7. 2000;82:1122-31. 4. Papagelopoulous PJ, Mavrogenis AF, Galanis EC, 11. Filippou DK, Papadopoulos V, Kiparidou E, Savvidou OD, Inwards CY, Sim FH. Clinicopatholo- Demertzis NT. 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Adamantinoma of tibia: a study of 12 cases. J Surg crete osteofibrous dysplasia. Clin Orthop Relat Res. Oncol. 2006;93:429-33. 2003;408:256-61. 8. Gleason BC, Leigl-Atzwanger B, Kozakewich HP, et 15. Soucacos PN, Hartofilakidis GK, Touliatos AS, The- al: Osteofibrous dysplasia and adamantinoma in chil- odorou V. Adamantinoma of the olecranon. A report dren and adolescents: A clinicopathologic reappraisal. of a case with serial metastasizing lesions. Clin Orthop Am J Surg Pathol. 2008;32:363-76. Relat Res. 1995;310:194-9.

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