SO-CALLED GRANULAR CELL MYOBLASTOMA OF THE THIGH WITH ORGANOID
STRUCTURE
PHILIP H. HARTZ,
M.D.
Public Health Service, Curasao N. W. I.
certainly not be described as dark staining. Often very
large or irregular nuclei were seen, though in general
they were of fairly uniform size. The protoplasm was
pale staining and contained several peculiar structures,
which could be easily distinguished by their staining
properties, form, and arrangement. They consisted of
homogeneous clumps or masses or thick threads, which
sometimes were lying close to the nucleus but in many
cells were arranged wreathlike in the periphery of the
cells. With the azan stain they were stained pale red,
though darker than the rest of the protoplasm; with
Masson's trichrome partly red, partly sepia-brown.
With iron hematoxylin they stained brown-black. In
some cells nearly all the protoplasm took a darker hue.
In sections stained with azocarmine-aniline blue many
CASE REPORT
cells contained small blue rods and granules. SomeA colored male, 40 years old, was admitted to the times they were very small, closely packed and indihospital for a tumor on the anterior aspect of the right vidually hardly visible, so that the protoplasm appeared
thigh, which had grown slowly. The tumor was lying to be uniformly blue, but in other cells the different
within the rectus femoris muscle. The patient was rods could be easily distinguished. They were never
operated upon (Dr. M. J. Hugenholtz) and the tumor arranged in parallel rows and nothing resembling cross
was removed together with a thin layer of surrounding striation was observed.
Though the tumor was very cellular, only few mimuscular tissue. The post-operative course was uneventful and at this moment, two years after the toses were found. They were only accepted as such
operation, the patient is still alive; it was however when centrosomes, achromatic spindles and chromosomes were present.
impossible to get information regarding his state of
The cells were arranged in small groups or alveoli
health.
The tumor was more or less sausage-shaped and sometimes containing only from 3 to 4 cells which were
measured 8 x 5 cm. The consistence was moderately surrounded by very thin septums, consisting of a few
firm. It was covered with a thin layer of muscular fibers and narrow capillaries. Several alveoli contained
tissue and was incompletely encapsulated. On section a central empty space. Small cavities were also seen,
the color was greyish; the cut surface showed several lined by pear-shaped tumor cells, which did not form
a continuous lining and projected into the cavity.
small hemorrhages.
Groups of cells were observed of which every individual
cell was surrounded by very thin fibers, staining blue
Microscopic Examination
Blocks of tissue, not thicker than from 3 to 4 mm., with the azan stain.
The groups of alveoli were divided by thicker sepwere fixed in the fluids of Bouin and Stieve* immediately after the removal of the tumor. The sections tums, which contained the larger vessels. However
were stained with azocarmine-anilin blue, Masson's tri- there were also tumor alveoli in close contact with wide
chrome, iron hematoxylin and hematoxylin-azophloxin. thin walled veins. In one thick septum there was a
• The tumor was composed of cells varying in size vein with a few tumor cells in the subendothelial layer.
from 20 to 80 microns. The larger cells contained Numerous small hemorrhages were observed throughsometimes from 3 to 4 nuclei. The nuclei were in out the tumor; often the central space of an alveolus
general oval, most of them with smooth contours. contained erythrocytes.
The tumor was surrounded by a capsule which conThey contained small chromatin granules and always
one, sometimes two, conspicuous nucleoli. They could tained muscle fibers in all stages of atrophy and which
in several places seemed to be invaded by tumor cells.
* Fixative of Stieve: Concentrated solution of HgCk Sometimes atrophic rriuscles fibers and tumor cells were
—76 cc; Formalin—20 cc.; Glacial acetic acid—i cc.
in close contact. Transitional forms between atrophic
582
Since 1926, when Abrikossoff described the first
"myoblastenmyoma," 120 cases of this tumor have
been reported, 1 though its muscular origin has not
yet been established beyond doubt. The tumors
were found in different locations, with a predilection for the upper parts of the digestive and respiratory tracts (67 cases). In 9 cases the tumors
were found in the muscles of the extremities.1
When these tumors attain a great size and show
an organoid pattern of growth, simulating tumors
originating in endocrine glands, the diagnosis may
be difficult. Of this the case to be reported is a
good example.
MYOBLASTOMA OF THIGH
583
endocrine glands. The possibility that we were
dealing with such a tumor was considered but
rejected on the grounds, that no primary tumor
muscle fibers and tumor cells were not observed and
there were no protoplasmatic junctions between these
two types of cells.
Uf
>o
h
ST'r
FIG. 1. GENERAL STRUCTURE OF THE TUMOR
Nucleoli visible. Azan-stain. X 280
FIG. 2. TUMOR CELLS SURROUNDING A THIN-WALLED VEIN.
DISCUSSION
It is evident from the description and the photomicrographs that there is a certain resemblance
between our tumor and neoplasms, originating in
X580
or metastases in other localisations were found and
that for the metastasis of a malignant tumor the
proliferative activity was too small. The fact that
the patient is still alive is also an argument against
584
PHILIP H. HARTZ
the existence of a primary malignant tumor. The
tumor, moreover resembled reported cases of myoblastoma (see fig. 4 of Horn and Purdy Stout 1 ).
However several differences existed. Geschickter2
described the nuclei of myoblastomas as small and
dense, Leroux and Delarue 3 as very chromophilic,
homogeneous and often with angular contours, and
Gray and Gruenfeld4 as small. In the case of
Grayzel and Friedman 6 the nuclei stained heavily
and contained sometimes nucleoli. The protoplasm is described as coarsely granular. According to Leroux and Delarue 3 mitoses were only
observed in one case, that of Derman and Golbert.6
of malignancy. Destruction of the walls of the
blood vessels with penetration into the lumen did
not occur.
The histogenesis of the myoblastomas is still
problematic. Gray and Gruenfeld reported a case
(their case 5) of a myoblastoma of the breast, the
structure of which suggested an origin from the
glandular structures of the breast; in our opinion
the cells also resembled the granular "onkocytes"
of Hamperl. Leroux and Delarue believe that the
myoblastomas are not real tumors but groups of
histiocytes, modified in a special way, for instance,
by the presence of small carcinomas. Gander9
FIG. 3. TUMOR CELLS SHOWING DARK STAINING PROTOPLASMATIC STRUCTURES.
In our case the nuclei were pale-staining, had
smooth contours, the nucleoli were conspicuous,
and a few mitoses were found. Also the protoplasm was more homogeneous than in the cases of
the authors cited. If our tumor belongs to the
same category as the myoblastomas already reported, these differences must perhaps be considered as variations also found in other groups of
tumors. According to Ewing' and the other
authors cited, most or all the myoblastomas are
benign; only Boyd 8 considers them as usually
malignant. In our case invasion of the tumor
capsule was observed. As many certainty benign
myoblastomas were found infiltrating the muscles
of the tongue, this does not justify the diagnosis
X500
proposes the distinction of two different kinds of
myoblastomas: tumors of the tongue, the cells of
which cannot be identified with myoblasts and tumors composed of "young" cells. Gray and Gruen-"
feld reject the resemblance of myoblastoma cells
to embryonal muscle cells, in which opinion we
cannot but concur; they believe that the lingual
tumors develop from muscle fibers undergoing
necrobiotic changes. In that case the lingual
myoblastomas cannot be considered as true tumors.
There remain however a certain number of myoblastomas which because of their structure must
be considered as real tumors; as long as their origin
is not exactly determined, they can best be designated as "so-called myoblastomas."
585
MYOBLASTOMA OF THIGH
SUMMARY
A case of so-called granular cell myoblastoma is
reported which differed in several respects from t h e
cases previously described. There were a few
mitoses a n d the tumor was infiltrating the capsule.
I t resembled tumors arising in endocrine glands.
T h e nature of t h e myoblastomas is discussed
briefly.
REFERENCES
(1) HORN, J R . ROBERT C , AND PURDY STOUT, ARTHUR:
Granular cell myoblastoma
Obst., 76: 315, 1943.
Surg., Gynec, &
(2) GESCHICKTER, CHARLES F.: Diseases of the Breast.
Philadelphia, J. B. Lippincott Company, 1943,
pp. 364.
(3) LEROUX, R., AND DELARUE, J.: Sur trois cas de
tumeurs a cellules granuleuses de la cavite buc-
cale. Bull. Assoc, franc, p . l'fitude du cancer,
28: 427, 1939.
«
(4) GRAY, S. H., AND GRUENPELD, G. E.: Myoblas-
toma.
Am. J. Cancer, 30: 699, 1937.
(5) GRAYZEL, DAVID M., AND FRIEDMAN, H. HAROLD:
Myoblastoma of the thoracic wall.
'31:512, 1941.
Arch. Path.,
(6) DERMAN, G. L., AND GOLBERT, Z. W\: fiber un-
reife, aus der quergestreiften Muskulatur hervorgehende Myome. Virchows Arch, f. path. Anat.,
282: 172-180, 1931 (cited by Leroux and Delarue) .
(7) EWING, JAMES : Neoplastic Diseases. Ed. 4. Philadelphia, W. B. Saunders Company, 1941, p. 247.
(8) BOYD, WILLIAM: Surgical Pathology. Philadelphia, W. B. Saunders Company, 1942, p . 773.
(9) GANDER, GEORGE: Du rhabdomyome granocellu-
laire de-la langue. Bull. Assoc, franj. p. l'etude
du cancer, 24: 56, 1935.