Collagenous fibroma (desmoplastic fibroblastoma): A unique presentation as a goiter in an 88-year-old man

RADIOLOGIC-PATHOLOGIC

CORRELATIONS

Collagenous Fibroma (Desmoplastic Fibroblastoma) : A Unique Presentation as a Goiter in an 8%Year-Old Man C’hri.sto/)herWilson, MD, J anna Summerall, MD, Jack Lubin, MD, and Thomas PV.Mesko, MD Collagenous fibroma (desmoplastic fibroblastoma) is a recently described entity in the medical literature. This entity has been reported in various locations, including the upper extremities, posterior neck, upper back, lower extremities, abdominal wall, and hip. We report an interesting case of an M-year-old man who presented with an apparent goiter involving the right anterolateral neck. Histologic studies revealed a well-circumscribed, paucicellular lesion composed of stellate and spindleshaped fibroblasts separated by bundles of collagen. No mitotic figures, necrosis, or calcification was observed. The stellate and spindle-shaped cells were positive for vimentin and focally positive for desmin, indicating myofibroblastic differentiation. Our case exemplifies the diagnostic difficulties that these tumors may pose from the clinical and radiologic standpoint when they clinically present as a goiter.

Ann Diagn Pathol4:

165-169,ZOOO. Copyright

Index Words: Collaeenous immunohistochemistry

F

IBROUS

ncoplnsms

comprise

an

fibroma,

estensi\.c

0 2000 by W.B. Saunders Company

desmoplastic

and

fibroblastoma,

goiter,

Xn 8%!,ear-old man \vas referred to our institution for possible surgical excision of a large right thl-roid mass that he lirsr noticed a fe\\ months before presentation. The mass caused some degree of local discomfort but 1va.snot associated \vith dyspnea or stridor. The patient’s medical histor) was signilicunt for hypertension and a cerebrovascular accident that occurred approximately 9 months before presentation. The patient reportedI!. had a surgical escision of a “fat9 tumor” from the para-esophageal area many years previous15 hwvevcr. \\‘e are unable to further elucidate the nature of this tumor. Following this procedure, the patient had a paralyed right vocal cord. Ph!xical examination revealed an approximately 7-cm, lirm mass in the right neck that seemed to arise from the right lobe of the t hyroicl gland. Preoperatkrc th!-roid chemisty profiles \wrc normal. Ultrasound of the th>Toid gland showed a 3.0-cm hypocchoic. nodule in\&ing the right midlobe (Fig I, left). ‘l‘h)nkl raclioioclinc scanning revealed a photopenic defect in the right lobr that bias not photopenic by technetium 99m. The impression ux that of a priman, tumor of the right lobe of the th!wid. A computed tomography scan of the neck, hwvcver, sho\\.ed a 3.7-cm, well-circumscribed, soft tissue lesion adjacent to, but not arising from, the right th)Toid lobe (Fig I, right). Also noted \vas a large superior-anterior mass that \\as radiologically interpreted as a mediastinal lipoma.

Subsccluentl~., the patient ‘l‘hc operative finclings \rere tumor that secmecl to involve

of Diagnostic

Pathology,

tissue,

Case Report

at

times ciiagnosticall~~ chnllcnging gro~q> of Icsions of the soft tissues. A distinct cntit!. originall!. termed ~esttro/~/~~.~lifJib~obko.~/otttn 112s recent 1).tlcscribccl b!. E\~ns’ and later rcnnmctl collagcnous libroma tq. Siclsen ct al.’ Thcsc tumors arc clinic&~ charactcrizccl as slo\vgrooving, painless inasscs that arc most commonly locatccl in the win, Ihllo\~ctl I,!. the shoulclcr, posterior neck, ~ippciback, hot, nnklc, leg, lm~l, abrlominal ~2111, nncl hip.’ \,Vc rcporl ;I cast of such a tumor in an 8%).car-old man \vlio prcsciitcd \vith \\hat \\.a~ thought to bc a goitci in\Aing the right lobe ol‘thc tlqwid gland. To the best of our kno~\4~l,gc, this is the onI\. cast 01‘ a collagcno~is libromn presenting as a goiter clinicall\. and mtliologicall\~.

Annals

soft

Vol4,

No 3 (June),

2000:

pp 165-l

undenvent

a neck exploration.

that of an extensive, librofatty the isthmus and anterior portion

69

165

166

Wilson et al

Figure 1.

(Left) Sagittal ultrasound of the right lobe of the thyroid gland demonstrating a homogeneous from the right lobe. (Right) An axial computed tomography scan of the neck at the level of the homogenous mass displacing the right jugular vein, the common carotid artery, and the thyroid lobe.

of the right lobe of the th)-roid gland. This tumor cstcntled deeply into the anterior metliastinum. Complete resection of the mass \va.s not possible. The portion of the mass \\ithin the neck \vas resected, including the th\Toicl isthmus and a subtotal resection of the right lobe of the th!-roicl glancl. The patient had an uncomplicated postoperati\.e period and has had significant relief from the preopcrnti\,e local discomfort that the mass initially produced. No recurrence has been documented to date. Materials

and Methods

Tissue for histologic examination was tisecl overnight in 10% bulTered formalin, scctioncd ~lt 0.2-cm intcl\.als, and embeddecl in parallin. Four-micrometer sections \vcre prcpared from the resulting blocks and stained \\-ith hematos)lineosin. Immunohistochcmical stains using the a\iclin biotinperoxidase technique I\-ith the Ibllo\\-ing antibodies \vere performed: vimentin (V9; Dako, Carpintel-ia, CA), dcsmin (D33; Dako), CD 68 (1:50; Dako), actin (HHF35; Dako), smooth muscle-specilic actin (I: 100; Dako), S-100 (l:5; Dako), calcitonin (1900; Dako), and thyroglobulin (1: 150; Dako). Results Grossly, the specimen consisted of a 4.0-cm bilobed soft tissue fragment with a firm to rubbelT consistent): The cut surface showed homogcnous, pale gra). tissue without any arcas of hemorrhage or necrosis. Microscopically, the tumor bvas well-circumscribed, hypocellular, and composed of stellate and spindieshaped cells within a collagenous stroma (Fig 2, top). The nuclei \raricd from oval to pyramidal in shape \\-ith

mass that appears to arise midthyroid gland showing a

occasional bizarre, multinucleated forms (Fig 2, bottom). Small cosinophilic nucleoli were noted. Mitotic a&it). leas rare and necrosis Ivas absent. There was no infiltration of surrounding tissues, but arcas with entrapped adipose tissue were found (Fig 3). Blood vessels were present, but sparse in distribution. Mast cells Ivere intermittently scattered within the collagenous stroma. Although there cvas an apparent intimate association of the tumor with the th)Toicl gland at the time of surgical cscision, estensi1.e sampling of the specimen failed to re\cal the prescncc of normal thyroid tissue. Immunohistochemical staining for limentin was strongI). positi\,e, Ivhereas that of dcsmin was focally positive, indicating m!.ofibroblastic diffcrcntiation. Actin, smooth musclespecific actin, S-l 00, th~roglobulin, and calcitonin were negative. CD 68 was negative in the spindle-shaped cells but positi1.e in the mast cells. The Icsion leas diagnosed as a collagcnous fibroma. Discussion Evans’ rcccntl>. introduced the term desnm/hsticJibroDhton~a to the medical literature w11cn hc described a series of seven cases with distinct morphologic characteristics. Subsequently, Siclsen ct al’ rcportcd an additional sewn cases and proposed that the tumor be renamed collagcnous fibroma. The argument given for renaming the tumor was that the original term clesn~o~lusticjhobhtornn misleads the reader to believe that the lesion consists of immature cells that induced a desmoplastic response b>. the host tissue. WC favor the term

Collagenous

Figure 2. (Top) A well-circumscribed mass composed of spindle cells within a collagenous stroma with interspersed blood vessels (scanning). (Bottom) High-power view demonstrating a bizarre multinucleated cell with conspicuous nucleoli.

Fibroma

Presenting

as a Goiter

167

’

collu,~enousfibl-onza because of its descriptive nature, which allows the rcadcr to understand that the lesion is a tumor of fibrous tissue with a prominent collagenous component. Eighty-four patients with this entity have been reported in the English literature.‘-’ The patients ranged in age from 5 to 83 years. There appears to be a male predominance, and the peak incidence is in the fifth to sixth decade of life.” Only one case has been described in a 5-year-old child.’ These lesions most commonly OCCLII in the subcutaneous and deep tissues of the arm, shoulder, neck, upper back, and lower extremity.3 Predilection for certain ethnicitys is unknown. This is prob-

ably due to the relatively low incidence of these neoplasms. The typical clinical presentation is that of a painless, slow-growing mass that is observed between 6 months to over 1 year before the patient seeks medical attention.3 To the best of our knowledge, presentation as a goiter has not been previously reported. Prior trauma was noted in a minority of patients. These tumors vary in size from 1 to 20 cm and appear to be well-circumscribed grossly, although microscopic infiltration of surrounding subcutaneous fat and muscle can be observed. The cut surface is pearl to tan-gray and homogenous, although cystic areas may be seen, espe-

168

Wilson

et al

Figure adipose

and necrotic cially in larger tumors. Is3 Hemorrhagic areas are not characteristic of this lesion. Microscopic examination shows a hypocellular, neoplastic process composed of spindle- and stellate-shaped fibroblasts interspersed in a fibromyxoid to densely fibrotic stroma. The stellate shape of these fibroblasts prompted one group of investigators to propose the term stellute cell _lih~rna.~ The cytologic characteristics described include oval or elongated nuclei with small eosinophilic nuclei that are surrounded by amphophilic cytoplasm. Mitotic activity is extremely low. There usually is little cellular atypia, but one case reportedly contained multinucleated cells similar to those described in our case.j Dystrophic calcification and metaplastic bone have been described one case.j The only consistent positive immunohistochemical stain reported in all the cases is vimentin. Various series and case reports show focal and moderate staining for HHF35, smooth muscle actin, factor XIIIa, and negative staining for CD-34, S-100, desmin, CD-68, cytokeratins, and epithelial membrane antigen.2-” These findings are suggestive of myofibroblastic differentiation. Electron microscopic studies have only been performed in one series.2 Ultrastructurally, the cytoplasm of the neoplastic cells is filled with dilated rough endoplasmic reticulum, focal filaments, and dense bodies. The nuclei are oval and elongated and contain prominent nucleoli. Clinically, these lesions are benign and all the cases report no recurrence with a follow-up period ranging from 1 to 3 12 months.‘-‘j Surgical excision appears to be curative. The differential diagnosis includes benign,

3. Area showing entrapped tissue. (Medium power.)

locally aggressive, and malignant soft tissue tumors, including neurofibroma, calcif+ng fibrous pseudotumor, giant cell fibroblastoma, fibroma of tendon sheath, solitary fibrous tumor, elastofibroma, sclerotic fibroma of skin, nodular fasciitis, desmoid tumor, and low-grade fibromyxoid sarcoma.“?0 One final point of interest is postulation of the tissue of origin in this case. We believe that in our case the tissue of origin could have been the prevertebral fascia surrounding the thyroid gland or the carotid sheath, which courses in close proximity to the thyroid gland. This would explain the close association of the mass with the endocrine organ. Previously reported cases could easily have arisen from numerous fibrous and connective tissues of the subcutaneous and deep tissues. Recent cytogenetic analysis of two cases has demonstrated chromosomal abnormalities of the long arm of chromosome 11 (1 lq12) and a possible genetic relationship to libroma of tendon sheath is suggested.” In summary, we report an interesting presentation of a collagenous fibroma of the neck that presented as a goiter. The clinical, gross, histologic, and ultrastructural features are those of a benign neoplasm. Cytologic atypia in these tumors should not be misconstrued as a feature of malignancy. Despite the relatively low number of cases presently reported in the literature, we are certain to see more of these peculiar lesions in the future due to the increasing awareness of these lesions. References I. Evans HL: Desmoplastic fibroblastoma: AmJSurgPathol 1995;19:1077-1081

A report

of seven cases.

Collagenous

Fibroma

Presenting

as a Goiter

tutnw

of soft

169

tissur:

A clinicopathologic

study o! I2 casts. Am J Surg Pathol 13. H;~srg;nva rhr soft

T. Hirose

tissue:

and

T, Srki

Ii, et al: Sol&q

An immul7ohist[~hrmic~l

,Ln J C:lin Pathol

IYYG; lOG:325-33

16. Shimizu of250

Ii.

.Ilontgomr~

spwtrum 9-~2-948

patirntn.

H.

Path&q

W,

.\lris

Ha!l)-

Enjoji

profile.

tumor.

anatomical fibrom~soid

a distinct

entit!.

21. S&t

analysis

Histopatholoo

R. Samson

libt-oma (drsmopl;tstic tendon shrath? \locl

1, Van

1991;35:

Finnish

CZlin Path01 1982:77:665-673

A clinicopathologic

Its morphologic

Surg Pathol

in the

AmJ

sarcoma:

faciitis: AmJ

desmoid

population.

Low-grade

An

distribution

age

C;LFCS.Am J Surg Psthol 1993:17:395-600 20. C;oodlacl,JR. .\lenzrl T, Fletcher

fasciitis:

E, et al: The

scs-. HL:

.Uodular

ICI-IF6

,JXl: Nodular

Incidence. III. Evans

of the skin. J Am Acad

,\I:

1984:l6:

P. N!k!ri

and

of

study.

study of elastoIibromas.

libromas

ancl immun~)histochemical

18. Rritam~~,IJ.

tumor

I

LE: Sclerotic I

S, Hashimoto

analysis

librous

and ultrastructural

14. Dixon AY. Lrr SH: An ultrastructural Hum Path01 1980: Il:257-262 1% Kapini RP. C;olitz Dermat~~l I989:20:266-27

immunohistochemical

I YY5: 19: 1257-I 265

sarcoma: C:DM:

A report

Low-grade

of ele\,rn

of

I2

librom!xoid

new cases in support

of

1993;26:229-237 den

Berghr

libroblastoma): C;em=tic Pathol 1999:12:565-368

H. et al: C:ollagenous link with

libroma

of