A case of synchronous dual hematological malignancy:
effects of multiple myeloma therapy on essential thrombocythemia and
vice versa
Nupur Krishnan1, Russell Price2,
Rouslan Kotchetkov 2*
1 University of Western Ontario, 1151 Richmond St,
London, ON, N6A 3K7; Canada
2 Simcoe Muskoka Regional Cancer Program; Royal
Victoria Regional Health Centre, Barrie, ON, Canada, L4M 6M2
Short Title: Synchronous MM and ET
*Correspondence: KotchetkovR@rvh.on.ca
Rouslan Kotchetkov
Department of Oncology, Simcoe Muskoka Regional Cancer Program; Royal
Victoria Regional Health Centre, Barrie, ON, Canada, L4M 6M2
Tel: +1-705-728-9090
Number of Tables: 2
Number of Figures: 2
Word count: 1780
Keywords: Essential Thrombocythemia, Multiple Myeloma, Dual
Hematological Malignancies
Abstract
We present a case of synchronous dual hematological malignancies:
multiple myeloma (MM) and masked essential Thrombocythemia (ET).
Excessive thrombocytosis due to bone marrow recovery occurred during
anti-myeloma therapy. Treatment for MM had no effect on ET; concomitant
ET did not decrease the efficacy of anti-myeloma therapies in this frail
patient.
Introduction
Dual malignancies occurring in the same patient are reported in the
literature [1]; however, dual hematological malignancies (DHMs) are
recognized less frequently [2-5] and are likely underreported
[6]. DHMs can been classified as either synchronous (SDHMs), when
occurring within six months of diagnosis of the first malignancy, or
asynchronous when occurring later [1]. Using a more restrictive cut
off of one month, we had earlier reported a 1.5% incidence of SDHMs in
patients referred to our cancer center [6]. The detection of DHMs
may be an incidental finding during routine bloodwork or during
investigation of discrepant clinical and laboratory findings [6].
The observed underreporting, and potential under detection, of SDHMs may
be because of masking from the primary malignancy [6]. DHMs
involving essential thrombocythemia (ET) and multiple myeloma (MM) are
quite uncommon, and most cases report MM developing years after ET
diagnosis. The occurrence of these two malignancies synchronously is
extremely rare. We report a case of concurrent MM and ET in a frail
elderly patient. We review the literature, discuss possible mechanisms,
and present potential challenges in the management of such patients.
Patient Information/ Clinical Findings
An 86-year-old female presented to the emergency in May 2016 with
confusion, hypercalcemia, and acute kidney injury. Her past medical
history included hypertension, hyperlipidemia, and osteoporosis. She was
brought to the clinic on a stretcher with an Eastern Cooperative
Oncology Group (ECOG) status of 4. On examination, she was disoriented
and had tenderness along her left rib cage. Investigations showed
hemoglobin (Hb) 82 g/L, macrocytosis (MCV 134), rouleaux, WBC 4.2
x109 with normal differential, and platelets 226 x
109/L (shown in Fig. 1A). Chemistry showed total
protein 99 g/L, albumin 26 g/L, calcium 3.15 mmol/L, and creatinine
clearance 17 mL/min. Total IgG was elevated (45.9 g/L) with reciprocally
decreased IgA and IgM. Monoclonal Protein (MP) was 41.8 g/L. Free Light
Chain (FLC) lambda was elevated (9,050 mg/L). Skeletal survey showed
osteopenia and a T12 vertebral compression fracture. Bone marrow (BM)
examination showed infiltration by plasma cells comprising up to 90% of
nucleated cells including occasional binuclear and atypical plasma cells
(PC) (shown in Fig. 1B). The PC were kappa restricted and had strong
cytoplasmic CD138+ expression (shown in Fig. 1C). Erythroid and
megakaryocytic maturation was reduced but normal morphologically.