MISLEADING LEADSBone Pain Caused by Isolated Paraspinal Extramedullary Relapse of Childhood

Acute Lymphoblastic Leukemia

Angela J. Alessandri, MD,2 Sheila L. Pritchard, MD,2 Bonnie G. Massing, MD,3

Michael A. Sargent, MD,4 Paul Theissen, MD,1 and Kirk R. Schultz, MD2*

Key words: acute lymphoblastic leukemia; extramedullary relapse; paraspinal mass;childhood cancer

Isolated extramedullary relapses of acute lymphoblas-tic leukemia (ALL) usually occur in the central nervoussystem or testes [1]. Other extramedullary sites are var-ied, but account for less than 2.5% of all relapses [2]. Weencountered a child with an isolated extramedullary re-lapse presenting as a paraspinal mass that compressed thelower brachial plexus nerve roots. The resulting radiculararm pain was first thought to be bony in origin.

The patient initially presented in July of 1992 as a27-month-old boy with a 2-week history of lethargy, dis-tended abdomen, night sweats, fever, and bruising. Onexamination, multiple bruises, petechiae, extensive ade-nopathy, and hepatosplenomegaly were evident. His tes-tes and neurologic status were normal. The initial inves-tigations are presented in Table I and were consistentwith a diagnosis of early B-cell ALL. The patient wasenrolled on CCG 1891 and randomized to regimen C,which included an intensified maintenance phase of threeweekly vincristine and prednisone pulses. A standard in-duction of vincristine, asparaginase, prednisone, and in-trathecal methotrexate was followed by consolidation,interim maintenance, a single delayed intensification,and 3 years of maintenance therapy. The bone marrow(BM) and cerebrospinal fluid (CSF) evaluations at theend of therapy were normal.

In April 1996, at 6 years of age and 7 months after thecompletion of chemotherapy, the patient presented withright arm pain. The exact location of the pain was diffi-cult to determine and there were no accompanying physi-cal signs locally or on general examination. Results ofthe blood work and bone marrow are presented in TableI. X-ray films of the right arm revealed no abnormalities.The pain improved transiently, but returned within a fewdays, at which time the patient was evaluated for possibleinfectious or rheumatologic disorders. A 5-week historyof dry cough was disclosed, prompting chest radiographythat revealed widening of the upper mediastinum consis-tent with a paraspinal mass (Fig. 1). Abnormal bonyuptake in the anterior aspect of one of the upper thoracic

vertebral bodies was seen on bone scan. Subsequent CTexamination revealed a right paravertebral mass withbone involvement in the pedicle and right lateral verte-bral body of T2 and extension into the spinal canal. Aright pleural effusion was also noted. Magnetic reso-nance image (MRI) confirmed the CT findings of a para-vertebral mass with an intraspinal, extradural componentthat distorted the spinal cord and compressed the sub-arachnoid space from C7 to T3 (Fig. 2). MRI of the headwas normal. Subsequent neurologic examination re-vealed subtle weakness of abduction of the right thumb.A biopsy of the mass revealed a monomorphous popu-lation of atypical lymphoid cells present in sheets. Generearrangement studies confirmed a B-cell monoclonalpopulation. The immunophenotype of the cells is pre-sented in Table I. A lumbar puncture undertaken 1 weekpostbiopsy, due to the risk of such a procedure with cordcompression, was normal (see Table I). Reinductiontherapy was commenced according to CCG 1941 withplans to proceed to a related donor bone marrow trans-

1Department of Paediatrics, University of British Columbia and BritishColumbia’s Children’s Hospital, Vancouver, British Columbia,Canada2Division of Pediatric Hematology/Oncology/Bone Marrow Trans-plantation, University of British Columbia and British Columbia’sChildren’s Hospital, Vancouver, British Columbia, Canada3Department of Pathology, University of British Columbia and Chil-dren’s and Women’s Health Centre of British Columbia, Vancouver,British Columbia, Canada4Department of Radiology, University of British Columbia and Chil-dren’s and Women’s Health Centre of British Columbia, Vancouver,British Columbia, Canada

*Correspondence to: Dr. Kirk R. Schultz, Department of Pediatrics,Division of Hematology/Oncology/Bone Marrow Transplantation,University of British Columbia, B.C.’s Children’s Hospital, 4480Oak St., Vancouver, B.C. V6H 3V4, Canada.E-mail: kschultz@interchange.ubc.ca

Received 2 January 1999; Accepted 10 February 1999

Medical and Pediatric Oncology 33:113–115 (1999)

© 1999 Wiley-Liss, Inc.

plantation at the end of intensification. Unfortunately,despite chemotherapy and irradiation to the paraspinalmass, the patient developed progressive disease at thissite. Palliative therapy was instituted, including selectiveirradiation to the multiple lytic bone lesions that devel-oped over the ensuing months. The patient died fromcomplications of acute lymphoblastic leukemia 7 monthsafter the diagnosis of his relapse.

DISCUSSION

Spinal cord compression has been reported as a rarecomplication of the initial presentation of leukemia inchildren, occurring in 0.4% of patients in one large series

TABLE I. Investigations at Diagnosis and Relapse

Investigation Diagnosis Relapse

Complete blood countWhite-cell count (×109/L) 14.6 6.08Hemoglobin (g/L) 61 135Platelets (×109/L) 10 225Neutrophil count (×109/L) 0.147 3.23Blast count (×109/L) 5.72 0

Bone marrow (% blasts) 90–100 (L1 morphology) Normal (<5)Immunophenotype (Peripheral blood) (Recurrent tumor)

CD10 70% 96%CD19 50% 17%CD20 19% 5%CD22 Not done 8%CD34 59% 5%Tdta Positive NegativeT-cell markers Negative Negative

Cytogenetics Hyperdiploid 52XXYY +13, +14, +21, +22 Not availableCerebrospinal fluid Negative Negative

aTerminal deoxynucleotidyl transferase—determined by slide peroxidase antiperoxidase method.

Fig. 1. Anteroposterior chest radiograph. A paravertebral soft-tissuemass is shown in the right medial lung apex.

Fig. 2. Midline saggital T1-weighted postgadolinium magnetic reso-nance image of the cervical and upper thoracic spine. The spinal cordis not visible between C7 and T3 due to compression and displacementby an intraspinal extension of the paraspinal mass. Contrast enhance-ment due to leukemic invasion is also shown in the T5 vertebral body.

114 Alessandri et al.

[3]. The only previous report of isolated extramedullaryrelapse presenting with cord compression in a child ap-peared in 1975 [4]. That patient differed from ours in thepresence of positive spinal fluid and in the features of thetumor (mainly connective tissue with small foci of lym-phoblasts). No immunophenotyping was available. Anadult case of T-cell ALL relapsing as an intradural spinalmass with CSF involvement has been reported [5]. TheB-cell phenotype and lack of CSF involvement in ourpatient distinguish him from the previous reports. Theantigen loss may be a result of clonal evolution, butcytogenetic analysis at relapse was not available. Suchevolution is unusual as ALL relapses generally representa reappearance of the original leukemic clone [6]. Ourpatient exhibited two favorable biologic features at diag-nosis (CD34-positive and hyperdiploid karyotype),which did not, however, preclude recurrence. The 5-yearevent-free survivals between the standard and intensivemaintenance arms of CCG 1891 are comparable, sug-gesting little contribution of the maintenance therapy tothe subsequent relapse [7].

Paraspinal masses are an unusual manifestation of iso-lated extramedullary relapse of ALL, but must be con-sidered in the differential diagnosis of any patient pre-senting with unexplained extremity pain. A lack of physi-cal findings or B-cell phenotype should not deter the

physician from further investigations, especially in ayoung child.

REFERENCES

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