The Spine Journal 13 (2013) e23–e27

Case Report

Myopericytoma of the thoracic spine: a case report and reviewof literature

Nikunj Agrawal, DNB Orth, Kushal Nag, MS*Department of Orthopaedics, Dr. Hedgewar Arogya Sansthan, Karkardooma, New Delhi 110032, India

Received 1 May 2012; revised 8 March 2013; accepted 14 June 2013

Abstract BACKGROUND CONTEXT: Myopericytom

FDA device/drug

Author disclosures

* Corresponding a

Arogya Sansthan, New

E-mail address: n

1529-9430/$ - see fro

http://dx.doi.org/10.10

a is a recently proposed term to describe a group oftumors originating from perivascular myoid cells. The tumor is most commonly located in the sub-cutaneous tissues and dermis of the extremities. Myopericytoma involving the skeletal system isa very rare entity, with only two such cases previously reported in literature.PURPOSE: To present only the third reported case of myopericytoma of the spine along with a re-view of literature.STUDY DESIGN: Case report with and review of literature.METHODS: We report the case of a 50-year-old woman who presented with pain in the back withgradual onset of paraparesis. Magnetic resonance imaging showed ill-defined signal changes in thebody and posterior elements of the vertebrae with epidural soft tissue mass encasing the spinal cord.RESULTS: The patient underwent excision of the lesion with spinal fusion followed by a shortcourse of radiotherapy. The patient recovered functional power after surgery, and at 32-monthfollow-up, there is no radiological evidence of recurrence of the lesion.CONCLUSIONS: Myopericytoma should be considered in the differential diagnosis of lytic le-sions of the spine. Surgery is curative; however, a short course of chemotherapy or radiotherapymay be required to prevent recurrent disease in case of incomplete tumor excision. � 2013 Elsev-ier Inc. All rights reserved.

Keywords: Myopericytoma; Thoracic spine; Lytic lesion

Introduction

Myopericytoma is a recently proposed term to describea group of tumors that originate from perivascular myoidcells and show a range of histologic growth patterns [1].It represents a subset of cutaneous adult myofibromas withthe proliferating cell being the myocyte. The most commonlocations for this tumor are the subcutaneous tissue and der-mis of the extremities. The spine is a rare site for myoper-icytoma, and only two such cases have previously beenreported in the literature [2,3]. In both these cases, the pa-tients presented with weakness, and the lesion involved theupper dorsal spine. One of the cases had findings of osteo-malacia (multiple pseudofractures and profound hypophos-phatemia with hyperphosphaturia), which resolved onremoval of the tumor. Surgical excision of the tumors with

status: Not applicable.

: NA: Nothing to disclose. KN: Nothing to disclose.

uthor. Department of Orthopaedics, Dr. Hedgewar

Delhi 110032, India. Tel.: 00919958505171.

ag_kushal@gmail.com (K. Nag)

nt matter � 2013 Elsevier Inc. All rights reserved.

16/j.spinee.2013.06.050

fusion was carried out in both the cases followed bya course of radiotherapy in one of them. At 2-yearfollow-up, none of the patients had any radiological evi-dence of recurrence of the tumors. The aim of this articlewas to review the available literature and report a third suchcase of thoracic myopericytoma to highlight this rare spinetumor, its differential diagnosis, and management.

Case report

An 50-year-old woman presented to us with chief com-plaints of pain in the upper back since 2 years and weaknessin both lower limbs that had gradually worsened over thelast 3 months. Spine examination revealed no gross defor-mity, although tenderness was present over the lower dorsalvertebra. Neurologic examination revealed paraparesis(Grade1/5 in right and Grade 2/5 in left lower limb). Therewas hypoesthesia below the eighth thoracic dermatome(T8) in the right lower limb. Deep tendon reflexes (kneeand ankle reflex) were exaggerated on the right side withextensor plantar. Magnetic resonance imaging of the spine

e24 N. Agrawal and K. Nag / The Spine Journal 13 (2013) e23–e27

(Fig. 1, Left, Middle and Right) revealed mild loss of heightof the eighth thoracic vertebra (T8), with abnormal ill-defined T1 hypointense and T2 hyperintense bone marrowsignal changes in vertebral body and posterior elements.Paravertebral and epidural soft tissue mass were seen en-casing and compressing the spinal cord with intramedullarysignal changes. 99m Technetium bone scan revealedincreased uptake in the midthoracic region and pointed to-ward a low-grade infective or mitotic pathology. Laboratoryvalues revealed normal levels of serum calcium, phospho-rous, parathyroid hormone, and calcitriol.

Surgery was planned and executed in two stages. In thefirst stage, excision biopsy of the lesion was done withanterior spine stabilization. In the second stage, posteriorelement resection of T8 vertebra with decompressionand instrumented fusion was done (Fig. 2). The excised tis-sue was sent for histopathologic examination. Histologyshowed a well-circumscribed lesion with numerous thin-walled blood vessels and walls of ovoid, plump, and spindleshaped cells. Cells had eosinophilic cytoplasm and grew ina conspicuous concentric pattern around the vessels (Fig. 3,Left and Right). Immunohistochemistry revealed the tumorto be smooth muscle antigen positive with negative reactiv-ity to desmin, h-caldesmon, cytokeratin, and CD34. Neuro-logic status of the patient improved significantly aftersurgery, with functional power in both lower limbs by the

Fig. 1. Sagittal section of MRI spine showing abnormal ill-defined T1 hypoint

vertebral body and posterior elements with axial sections (Right) revealing para

magnetic resonance imaging.

third postoperative day. Patient was mobilized with a Taylorbrace, and a course of physiotherapy was initiated. A5-week course of radiotherapy was given, with a total of45 Gy being administered. She was followed up at 3-monthintervals, and presently, at 32 months postoperatively, thepatient has regained full motor power in both lower limbswith no radiological evidence of recurrence of the lesion.

Discussion

Myopericytoma is an unusual perivascular tumor that ap-pears to be a hybrid between hemangiopericytoma and an-giomyoma [4]. The term myopericytoma was firstproposed in 1996 to describe a subset of cutaneous adultmyofibroma with the proliferating cell being the myocyte,an intermediate cell between the pericyte and smooth musclecell, in a myofibromatosis-like hemangiopericytoma [5].The term was adopted in 1998 by McMenamin and Fletcher[6] to describe a spectrum of benign tumors characterizedhistologically by concentric perivascular proliferation ofspindle cells, showing apparent myoid differentiation. Myo-pericytoma occurs over a wide range from second decadeonward, with a consistently reported male predilection. Itusually presents as single or multiple subcutaneous noduleson the extremities, with rare cases of multicentricity [7].

ense (Left) and T2 (Middle) hyperintense bone marrow signal changes in

vertebral and epidural soft tissue mass compressing the spinal cord. MRI,

Fig. 2. Postoperative X-ray, anteroposterior, and lateral views showing instrumented fusion with bone grafting.

e25N. Agrawal and K. Nag / The Spine Journal 13 (2013) e23–e27

Myopericytoma affecting the skeletal system is a rare occur-rence with only two such cases being reported in literature.In both the cases, the tumor occurred in the thoracic spine in-volving the T3 [2] and T5 and T6 [3] vertebrae, respectively.The primary presenting symptom in both the cases wasweakness of the extremities with back pain being reportedby one of the patients (Table 1). The patient who had com-plaints of back pain on further investigation revealedfeatures of secondary hyperparathyroidism (hypophosphate-mia, hyperphosphaturia, and increased parathyroid hormone

Fig. 3. Photo micrographs showing a vascular tumor composed of dilated vascula

(Right) (hematoxylin and eosin stain; magnification: Left, �100; Right, �200).

with decreased calcitriol levels) with radiological evidenceof compression fractures at multiple levels from T5 to T11and Looser zones. Thus, a diagnosis of oncogenous osteo-malacia was established. Both the patients underwentsurgery with an intraoperative tissue sample sent for histo-pathologic examination. Histopathology in both the casesshowed concentric perivascular proliferation of round tospindle cells withmyoid differentiation compatiblewith a di-agnosis of myopericytoma. Immunochemistry revealeda pattern consistent with myopericytoma (Table 2). Both

r spaces (Left) and the walls of which contain several layers of myoid cells

Table

1

Synopsisofrelevantfindingsin

reported

casesofmyopericytomaofthespine

Author(year)

Patientageandsex

Level

oflesion

Presentingsymptoms

Associated

findings

Treatment

Complications

Follow

-up

Cox

andGiltm

an(2003)[2]

70yandmale

T3

Weaknessofrightleg

andupper

extrem

ities

None

Excision

oflesionand

radiotherapy

Nil

Norecurrence

at32mo

Brunschweileret

al.(2009)

[3]

43yandfemale

T5andT6

Upper

backpainwithproxim

al

muscle

weakness

Osteomalacia

Embolization,

tumorremoval,

andT5–T6hem

icarpectomy

withfusion

Nil

Recurrence

ofosteomalacia

andnoradiologicalevidence

oflocalrecurrence

at24mo Table 2

Immunochemistry in reported cases of myopericytoma of the spine

Author (year) SMA h-Caldesmon Desmin Cytokeratin CD 34

Cox and Giltman

(2003) [2]

þ � � � �

Brunschweiler et al.

(2009) [3]

þ � � � �

SMA, smooth muscle antigen.

e26 N. Agrawal and K. Nag / The Spine Journal 13 (2013) e23–e27

the tissue samples were positive for smooth muscle antigen,thereby indicating myoid differentiation [3]. The other im-munostatins including CD 34,cytokeratin, desmin, and h-caldesmon were negative although 9% of cases of myoperi-cytoma have been reported to be focally reactive to desmin[8]. Myopericytoma is a benign tumor, although rare casesof malignant myopericytoma have been reported [1]. Thedifferential diagnosis of a lytic lesion of the spine at thisage group would commonly include malignant metastasisand multiple myeloma. Among other causes, infection,chondrosarcoma, lymphoma, chordoma, neurofibroma, andhemangioma can be considered [9,10]. Primary hemangio-pericytoma of the bone is very rare, with even fewer casesreported in the spine [9–14]. Two types of hemangiopericy-toma have been observed in the spine [15]: intraspinalmeningeal hemangiopericytoma and osseous hemangioperi-cytoma, with primary hemangiopericytoma of the vertebraebeing the most rare. Although myopericytoma resemblesa hemangiopericytoma in certain aspects, there are enoughdistinguishing features to classify this lesion as a separateentity. In the cases of spinal hemangiopericytoma previouslydescribed, although the original diagnosis was a hemangio-pericytoma, reevaluation of all hemangiopericytoma of thespine may lead to some of these lesions to be better classifiedas a myopericytoma. Treatment of choice is surgical exci-sion with or without fusion as required in each individualcase. In cases of hemangiopericytoma, data suggest a roleof radiotherapy and chemotherapy in large unresectable tu-mors to enable subsequent resection, in case of metastasis,or after microscopic incomplete excision [16,17]. In one ofthe cases described above, a small amount of tumor tissuewas left behind, and no postoperative radiotherapy wasgiven, leading to recurrence of signs of oncogenous osteo-malacia [3]. Hence, we believe that a short course of radio-therapy is indicated in myopericytomas of the spine,especially if there has been incomplete tumor excision, toprevent local recurrence. We hereby present only the thirdreported case of a myopericytoma of the spine along witha review of literature to highlight this rare entity andconsider it in the differential diagnosis of lytic lesions ofthe spine.

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