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293

Visceral Metastases Melanoma: Findings

from on MR Imaging

.

.

.

Ahalya Prernkumar1 Linda Francesco Irwin

Sanders2 Manncola3

Feuerstei& Rendoll Concepcion3 Douglas Schwartzentruber

Typical

ocular

and NS

(STIR) pulse sequences. on Ti-weighted lesions). Less

hypointense

MR

images.

Most commonly,

sequences frequently,

or isointense

lesions were either hypointense

or isointense

and hyperintense on T2-weighted and STIR sequences lesions were hyperintense on Ti-weighted sequences

on T2-weighted

and STIR sequences

(185 and

(59 lesions). A mixed

was seen on Ti- and T2-weighted sequences in 17 lesions. The patterns did not correlate with lesion size. Of the three sequences studied by subjective comparison, the STIR sequence in our series had the highest sensitivity for lesion detection and yielded the highest lesion conspicuity. Injection of gadopentetate dimeglumine in Ii patients did not increase either the number or the conspicuity of lesions seen. Our results show that visceral metastases from melanoma have a wide variety of appearances on MR images. The STIR sequence appears to be optimal, and the metastases do not enhance with gadopentetate dimeglumine. pattern

AJR 158:293-298,

February

1992

Malignant melanoma is a relatively common neoplasm, with an incidence of 10 per 100,000 population per year [i]. The incidence has increased in recent years, probably because of increased exposure of patients to sunlight and early

cases

detection.

Received June 24, 1991 ;accepted after revision August29, 1991. Presented at the annual meeting of the American Roentgen Ray Society, Boston, MA, May 1991. I Department of Diagnostic Radiology, Bldg. 10, Room 1C660, Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892.

Address reprint requests to A. Premkumar. 2 Department of Diagnostic Radiology, Columbia Presbyterian Medical Center, New York, NY 10032. 3 Surgery Branch, National Cancer Institute, National Institutes of Heaith, Bethesda, MD 20892.

0361 -8o3x/92/1 C American

582-0293

Roentgen

Ray Society

The mean

age at presentation

for stages

1 and 2 melanoma

is 45 years

[1]. A sensitive method that does not require ionizing radiation is needed for screening, detecting, and monitoring the response to therapy of visceral metas-

tases. There has been much interest recently in the MR imaging of malignant melanoma. Most imaging studies, however, have concentrated on the orbits [2-5], intracranial structures [6, 7], or cutaneous lesions [8, 9], and little information is available on metastatic melanoma involving the viscera. We reviewed the MR examinations of 48 patients with malignant melanoma and metastases to various parts ofthe body, excluding the orbits and brain, to determine if there was any predominant MR finding specific for this tumor and to see if visceral metastases from melanoma had MR characteristics similar to published descriptions

of melanoma

metastatic

to the CNS.

We analyzed

to determine which sequence optimally visualized were also reviewed to determine the enhancement

various

pulse

.. .

..

.

melanomas

on T2-weighted

.;. -

are hypenntense on Ti-weighted MR images and We performed MR imaging in 48 patients with melanoma metastatic to visceral organs. Images were reviewed retrospectively in order to determine whether there were predominant MR features specific for visceral melanoma and to see if visceral metastases have MR characteristics similar to metastases in the NS. Eleven patients also were examined after injection of gadopentetate dimeglumine to evaluate the enhancement characteristics of these tumors. Two hundred sixty-one lesions were found. Lesions were classified according to their signal intensities relative to uninvolved liver on Ti-weighted, T2-weighted, and short TI inversion recovery hypointense

:

.,

.

,

sequences

the lesions. Enhanced images characteristics of these lesions.

. .,.,

-

PREMKUMAR

294

Materials and Methods Selection

of Cases

Forty-eight

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cluded

patients

with

in the study.

oncologic

data

known

metastatic

We obtained

bases.

These

patients’

are

names

melanoma

names

were

in-

from the MR and

of patients

with

ET AL.

AJR:158,

February

1992

score was noted separately for T2-weighted and STIR sequences, as they differed occasionally. The sequence(s) that provided the highest lesion conspicuity (i.e., greatest visual signal-to-noise ratio) for each patient was determined subjectively.

malignant

who had MR imaging at this institution from June 1 , 1988, to December 31 , 1 990. All MR studies were performed in the course of routine clinical care, and informed consent was obtained from all patients before scanning. Metastatic melanoma was diagnosed on the basis of biopsy findings of at least one distant site in all cases. When the patient had only one site of metastasis, this was almost melanoma

invariably

was site

sampled

when was

by

multiple sampled,

biopsy.

The

lesions and

only

involved

it was

time

several

assumed

that

biopsy

was

organs; the

not

then,

other

done

only

lesions

one

repro-

the same abnormality. The patients were 20-74 years old 44 years), and the group had 28 men and 20 women. The initial diagnosis of melanoma was made from 2 weeks to 26 years (mean, 4-5 years) before the MR examination. The sites of the primary lesions included predominantly the trunk, extremities, head, and neck. The primary site was unknown in seven patients. sented (mean,

Imaging

MR

imaging

was

performed

Highland

Heights,

on a 0.5-T

Picker

OH) in 41 patients,

scanner (Picker on a 0.5-T Gyro-

scan (Philips Medical Systems, Shelton, CT) in four patients, and on a 1 .5-T Signa scanner (General Electric, Milwaukee, WI) in three patients. Pulse sequences were performed as follows: 48 patients had contiguous axial Ti -weighted spin-echo scans, 300-500/i 2-20/ 8 (TA/TE/excitations), with a 1 28 x 256 matrix and 1 0-mm slice thickness; 34 patients had contiguous axial T2-weighted spin-echo scans, 2000/80-1 00/4 (TA/TE/excitations), with a 160 x 256 matrix

and 10-mm slice thickness; coronal

short

i40/26-30/4

TI inversion

and 40 patients had contiguous recovery

(STIR)

(TR/Tl/TE/excitations),

scans,

1 500-1

axial and 640/i

with a 1 60 x 256 matrix

Lesions

relative to the appearance on rather than the comparison so or hyperintense.

Lesions

metastases

were

seen on eight

(53%).

Of 35 abdominal

MR

images reviewed, the liver was involved on 27 (77%), adrenal metastases were seen on eight (23%), and splenic metastases were seen on three (8%). Of a total of 63 images lymph

node

involvement

was

seen

on i 5 (24%)

and metastases to the muscle and bone were seen in 19 (30%). The MR signal-intensity patterns were analyzed in detail and then simplified into four main categories: (i) hypointense or isointense on Ti -weighted images and hypenntense on T2-weighted images (1 85 lesions), (2) hyper-, iso-, or hypointense on Ti -weighted images and hypointense on T2weighted

images

(40 lesions),

on Ti -weighted

images

(3) hyper-,

iso-, or hypointense

and isointense

on T2-weighted

ages (i 9 lesions), and (4) mixed or hyperintense images (i 7 lesions). Of the i 48 lesions

were

defined

as

being

hypo-

or

and results was scored hyperintense

signal intensity of the liver on the basis of their the filmed image. We used the liver’s signal intensity signal intensity of the surrounding normal tissue for that we could standardize what we labeled as hypoThis was particularly useful as we had several lesions

fat and nodes, where the surrounding

subcutaneous

images

with

included

(nine lesions), lung and spleen (six lesions each), intraabdominal fat (four lesions), and miscellaneous sites (four lesions). The frequency of involvement of each of these sites was as follows: of i 5 chest MR images that were reviewed, lung

and

tissue

was fat and a lesion would always be hypointense compared with it on a Ti -weighted sequence. The different sequences were photographed in a standard routine way, and no effort was made to enhance or detract the image by using different windows. Lesions were categorized into four main types based on their Ti characteristics as isointense, hypointense, hyperintense, and mixed. Each category was then further subdivided into four subtypes based on the signal of the lesion on T2-weighted images. For example, a lesion that was isointense on Ti -weighted images and hyperintense on T2weighted

261 lesions. The sites of involvement

images and mixed or hyperintense (in 23 patients)

im-

on Ti

-

on T2-weighted

in the liver, the distribution

was as follows: 84 lesions fell into category i 33 lesions into category 2, i 6 lesions into category 3, and 15 lesions into category 4. The maximal diameter of the lesions ranged from 0.5 to 1 0 cm (mean, 2.8 cm). The MR signal characteristics ,

were independent of the size of the lesions.

The MR images were evaluated by two radiologists, were arrived at by consensus. Each pulse sequence

in the

We detected

liver (1 48 lesions), lymph nodes (43 lesions), muscle and bone (28 lesions), subcutaneous fat (i 3 lesions), adrenal glands

weighted

Analysis

individually.

of MR Sequences

00-

10-mm slice thickness. Gadopentetate dimeglumine, 0.1 mmol/kg (Berlex, Plainfield, NJ), was injected IV in 1 1 patients. We performed 35 MR examinations of the abdomen, 1 5 of the chest, five of the pelvis, eight of the neck, and three of the spine.

Image

Analysis

reviewed,

Techniques

International,

Results

rings

would

fall into

around

them

the

main

were

category

grouped

i and

separately.

subtype

c.

Lesion

All 43 lesions (in ii patients) seen in the lymph nodes fell into category 1 The lesions ranged from 0.5 to 7.0 cm (mean, 2.7 cm) in maximal diameter. .

In the spleen (six lesions in two into category i two into category

4. The maximal cm

(mean,

independent

diameter

3 cm).

patients),

two

lesions

fell

2, and two into category of these lesions ranged from i to 5

,

Again,

the

signal

characteristics

were

of the size of the lesions.

Of the nine lesions (in seven patients) in the adrenal gland, four fell into category into categories

i three into category ,

2 and 3. The sizes

ranged

4, and one each from

i to i 0 cm

(mean, 4.i cm). There was no correlation again between the MR signal intensity and size of the lesion. There were 28 lesions (in 14 patients) in the muscle and bone. Of these, 24 fell into category i two into category 3, and two into category 4. The lesions ranged from i to i 3 cm (mean, 4.5 cm) in maximal diameter. The lesions seen in categories 3 and 4 were similar in size to those seen in category 1. ,

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AJR:158, February

MR OF VISCERAL

1992

METASTASES

Of the six lesions (in six patients) in the lung, five fell into category i and one into category 3. The lesions ranged from i to 5 cm (mean, 2.5 cm) in maximal diameter. In the subcutaneousfat(i 3 lesions in eight patients), nine were in category i two in category 2, and one each in categories 3 and 4. These ranged from 0.5 to 3 cm (mean, 1 .5 cm) in maximal diameter. The lesions in the lymph nodes and a majority of lesions in the liver appeared to fall into category i There was, however, no correlation between the signal intensity patterns and the size of the lesions. Different lesions in the same patient also showed different signal-intensity patterns. ,

.

Thirty-four

imaging

patients

with

1 83

lesions

had

all three

MR

(Ti-weighted, T2-weighted, STIR). The pulse sequences providing the greatest conspicuity of each individual lesion were as follows: 139 lesions (76%) were best seen on the STIR sequence, 33 lesions (i 8%) were seen equally well on T2-weighted and STIR, six lesions (3%) were seen best on Ti -weighted, two lesions (1 %) were seen best on T2-weighted, and three lesions (2%) were not seen at all on any of the sequences. Of note, eight lesions were detected on STIR images only, as they were isointense on Ti and T2weighted images. Six lesions (3%) were detected on Ti-

MELANOMA

295

remaining 32 lesions were seen better on T2-weighted images. When Ti -weighted and STIR were the two sequences used (for 40 lesions), STIR was better in 36, Ti -weighted was better in two (where the lesion was isointense on STIR), and two lesions were seen equally well on both sequences. Eleven patients with 21 lesions were studied after injection of gadopentetate dimeglumine. Of these, seven lesions were in the liver and the others were more orless equally distributed among other organs. No enhancement was seen in i 4 lesions, slight enhancement was seen in five lesions, and moderate enhancement was seen in two lesions. The enhanced images did not increase lesion conspicuity when compared with the unenhanced

images.

sequences

-

weighted

FROM

images

only

and were

isointense

on T2-weighted

and STIR images. When Ti-weighted and T2-weighted sequences were the only two sequences performed, the lesion was characterized better on Ti -weighted images in five instances, and the

Discussion Malignant melanoma is a very aggressive cancer known to metastasize widely [i 0, i i ]. The incidence of metastases appears to be strongly influenced by the stage of the primary lesion [i 2, i 3]. CT continues to be the main technique used to diagnose and stage visceral metastatic melanoma [i 4-i 7]. Little, however, has been published about the MR characteristics of visceral metastatic melanoma [i 8]. On MR, ocular and CNS melanomas are hyperintense on Ti -weighted images and hypointense on T2-weighted images. Several theories have been postulated to explain the imaging characteristics of these tumors, including their mela-

Fig. 1-54-year-old man with melanoma metastatic to liver and splien. A, Ti-weighted MR imag. of abdomen shows two hyperintense hepatic maues (arrows) and hypointense splenic mass surrounded by hyperintense ring. B, STiR MR image shows that hepatic lesions are now hypointense (arrows), and spl.nlc Ission Is now hypenntense with a hypointense rin

Fig. 2-63-year-old woman with melanoma metastatic to liver and lung. A, Two hypointense hepatic masses are seen on Ti-weighted MR Image. B, On STiR MR image, messes are now hyperlnt.nse.

A

B

296

PREMKUMAR

and the hemorrhage frequently associated with them [19]. Our study showed a spectrum of changes on MR. Typical findings in the body differed, however, from the typical findings of CNS and ocular melanomas mentioned earlier. Only 26 (1 0%) of 261 lesions showed hyperintensity on Ti weighted images and hypointensity on T2-weighted or STIR images (Fig. i). Ten lesions (4%) were hypenntense on Ti weighted but stayed isointense on T2-weighted or STIR images. The most common MR finding was a hypointense mass on Ti -weighted images that was hyperintense on T2-

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or STIR

images

(Figs.

2 and 3). This

to one -

-

appearance

can be seen with other pathologic changes and is not specific for melanomas. A ring surrounding the lesion was detected in i 3 lesions (5%) (Fig. 4). Although ring lesions themselves are not specific, melanoma should be considered in the differential diagnosis, especially if the lesions also appear hypointense on T2-weighted or STIR sequences. This signal characteristic (i.e., hypointensity on T2-weighted images) is unusual on MR. Other entities that may cause it, besides melanoma, include hemorrhagic lesions and regenerative nodules [20]. It is of interest to note that a spectrum of findings was seen on MR images of the same patient. In fact, lesions

-4

T

AJR:158,

February

1992

in the same organ showed different imaging characteristics. The MR imaging characteristics were independent of the size of the lesion. The three sequences in our study were complementary

nm content

weighted

ET AL.

another

in showing

the

lesions,

but

the

STIR

so-

quence was the most sensitive and useful in localizing the metastases (Fig. 5). Comparison of T2-weighted and STIR sequences showed that eight lesions were detected on STIR sequences that were isointense and not seen on T2weighted sequences. Conversely, no lesions detected on T2-weighted sequences were missed on STIR sequences. Although, to our knowledge, none of our patients had cirrhosis or fatty infiltration, it is conceivable that the presence of these changes could influence the MR characteristics of the individual lesions. For example, a lesion that would have been hyperintense on Ti -weighted sequences, relative to normal liver, could conceivably appear isointense with a fatty infiltrated liver; or a lesion that would have been hypointense relative to the liver on the STIR sequence could conceivably appear isointense and be missed in the presence of fatty infiltration,

as the STIR

sequence

from a fatty liver. Gadopentetate dimeglumine

would

suppress

was not helpful

the signal

(Fig. 6). Be-

.

Fig. 3.-30-year-old man with melanoma metastatic to pelvis. A, TI-weighted MR Image shows hypointense masses involving right iliac region (solid arrows) arid both sides of sacrum (open arrows). B, Hyperintense masses are seen better on STIR MR image owing to greater lesion-to-back-

ground contrast.

Fig. 4.-59-year-old man with melanoma metastatic to liver and right paratracheal area. A, TI-weighted MR image shows hyperin. tense right-sided hepatic mass. B, STIR MR image shows that mass is hypoin-

tense with hyperintense

ring.

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AJR:158,

February

1992

MR OF VISCERAL

METASTASES

FROM

Fig. 5.-68-year-old man with melanoma metastatic to liver and adrenal glands. A, TI-weighted MR image shows lsolntense mass in left adrenal gland (short arrow), mixed-signal-intensity arrow), and hypointense mass near portal vein (white arrow). B, T2-weighted MR Image shows that hepatic mass and mass in right adrenal gland are hyperintense. C, Hyperintense adrenal messes are seen better on STiR MR image.

Fig. 6.-59-year-old man with melanoma metastatic A, STiR MR image shows hypointense hepatic mass B, Mass Is Isointense with liver and, therefore, is not C, Ti-weighted MR Image obtained after injection of

297

MELANOMA

mass

in right

adrenal

gland

(long

black

to liver and brain. (arrow). seen on TI-weighted

gadopentetate

MR image. dimeglumine also does not show

cause most lesions are hypointense relative to normal liver parenchyma with Ti -weighting, tumor enhancement actually obscures lesions in certain instances. Hyperintense lesions are already rather obvious, and additional hypenntensity was not beneficial. The number of patients studied with gadopentetate dimeglumine was small, however, and further work is needed to conclusively determine the role of this agent. Many of our patients were on immunotherapy protocols at the time of MR imaging, and it is speculative what part this played in changing the MR signal. Further work, before and after treatment, must be done to determine this conclusively. In conclusion, this study shows the wide spectrum of changes seen with MR for visceral metastatic melanoma. The

mass.

STIR sequence appears to be the best for imaging lesions. In the limited number of cases studied after injection of gadopentetate dimeglumine, it did not enhance detection of lesions. REFERENCES 1 . Baich CM, Houghton A, Peters L. Cutaneous Hellman 5, Rosenberg SA, ads. Principles Philadelphia: Lippincott, 1989:1499-1542

2. Peyster RG, Augsburger

melanoma. and practice

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JJ, Sheilds JA, et al. Intraocular tumors: evalua1988;168:773-779 3. Wilms G, Marchal G, Decrop E, van Hecke P. Baert A, Dralands G. Surface coil magnetic resonance imaging of the orbit at 1.5T. ROFO tion with MR imaging.

1988;149,5:496-501

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L, Allewaert R, deLaey JJ, Verbraeken H, Bittoun J, van do Velde E. High field resolution magnetic resonance imaging of malignant choroidal melanoma. lnt Ophtha!mol 1988;i 1:199-205 zimmerman RA, Bilaniuk LT. Ocular MR imaging. Radiology 1988;168:875-876 Woodruff WW Jr, Djang WT, MCLendOn RE, Heinz ER, Voorhees DR. Intracerebral malignant melanoma: high field strength MR imaging. Radio!ogy 1987:165:209-213 Weindling SM, Press GA, Hosselink JR. MR characteristics of a primary melanoma of the quadrigeminal plate. AJNR 1988;9:2i4-2i5 Zemtsov A, Long R, Bergfield wF, Baum PL, Ng TC. Magnetic resonance imaging of cutaneous melanocytic lesions. Dermato! Surg Once! 1989;i5:854-858 Schwaighofer BW, Fruehwald FXJ, POhI-Markl H, Neuhold A, Wicke L, Landrum WL. MRI evaluation of pigmented skin tumors. Invest Radio!

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Lee YN. Malignant melanoma: pattern of metastases. CA 1980:30: 137-141 Patel JK, Didolkar MS, Pickren jw, Pickren Jw, Moore AM. Metastatic pattern of malignant melanoma: a study of 21 6 autopsy cases. Am J Surg 1978;135:807-8i0 Herlyn M. Human melanoma: development and progression. Cancer Me-

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Rev 1990;9:lOi-112 A. Thickness, cross-sectional areas and depth of invasion in the prognosis of cutaneous melanoma. Mn Surg 1970;172:902-908 14. Bydder GMF, Kreel L. Body computed tomography in the diagnosis of malignant melanoma metastases. J Comput Tomogr i981;5:2i-24 tastasis

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kTagrng, histopathology, and electron paramagnetic resonance. J Comput Assist Tomogr 1990:14:547-554 MurakamiT, Kuroda C, MarukawaT, et al. Regenerating nodules in hepatic cirrhosis: MR findings with pathologic correlation. AJR 1990;155: 1227-1231

Visceral metastases from melanoma: findings on MR imaging.

Typical ocular and CNS melanomas are hyperintense on T1-weighted MR images and hypointense on T2-weighted MR images. We performed MR imaging in 48 pat...
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