OCCURRENCE OF DECIDUA-LIKE TISSUE IN T H E LUNG
REPORT
OF A C A S E
PHILIP H. HAHTZ, M.D.
Hospital Vargas, San Cristobal, Tachira, Venezuela
Examining lungs from pregnant women in a search for embolic trophoblast,
W. W. Park 8 found a small fragment of tissue which closely resembled decidua
in the lung of a 26-year-old woman who died of bronchopneumonia with abscess
formation and empyema 4. hours after delivery of a normal child. The tissue
was lying 6 mm. beneath the pleura and measured 250 by 200 microns. Only 6
sections were available for study. After using different staining procedures and
comparing the tissue with sections of cytotrophoblast, syncytiotrophoblast,
myometrium, liver, a fragment of hepatoma and with displaced and metaplastic
bronchial epithelium, the author came to the conclusion that the morphology
and staining reactions strongly indicated that the tissue was decidual.
Concerning the origin of the tissue in the lung, three possibilities were considered: (1) that before pregnancy, blood-borne endometriosis was present
which subsequent to pregnancy underwent a decidual reaction, (2) that the
tissue arose by a process of differentation in situ, or (3) that decidua was carried
by the bloodstream from the placental site. Since endometrial tissue has been
observed only twice in the thorax, in both instances in the pleura, and never in
the lung,2' 6 the possibility that it arose through decidual reaction in an already
existing focus of endometriosis was considered slight. That it arose through
metaplasia or differentation in situ was considered theoretically possible, but in
view of the frequency of emboli of trophoblastic tissue to the lung, an analogous
process, the third possibility was preferred.
No similar cases were found in the literature but Dr. Park kindly informed me
that he had observed a second case. To these cases I will add a third, observed
almost nine years ago.
R E P O R T OF CASE
A 24-year-old pregnant woman with mitral stenosis was hospitalized because of hemoptysis. She died in the fourth month of pregnancy with symptoms of congestive cardiac failure,
anginal pains, and probable pulmonary infarction (Dr. A. van der Sar).
Autopsy was performed very soon after death so that a living fetus could be extracted
from the uterus. There was dilatation of both the left and the right atrium, dilatation and
slight hypertrophy of the right ventricle, mitral stenosis, and chronic endocarditis of the
aortic valve. The heart weighed 310 grams. The lungs were fairly firm; the pleura of the
lower lobe of the right lung showed fibrinous deposit, the color of the lungs on section was
brown; there were many foci of condensation and numerous small hemorrhages. The other
findings were not relevant.
Microscopic examination. Numerous thin blocks of tissue were fixed in the Bouin-sublimate mixture. They were embedded in tissuemat with Petcrfi's methylbenzoate-celloidin
Received, August 16, 1955; accepted for publication September 2.
Dr. Hartz is Pathologist.
48
Jan. 1956
49
DECIDUA-LIKE TISSUE IN LUNG
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Fio. 1 (upper left). Islet of deeidua-liko tissue. Hematoxylin azophloxin stain.
X 175.
Kid. 2 (upper right). Tangential section. Groups of "heart-failure" colls surrounded by the large cells. X 350.
Kirs. 3. (lower). Same as Figure 1. X 350.
50
HARTZ
Vol. 26
method and the sections stained with hematoxylin azophloxin, Heidenhain's azan stain,
with hematoxylin-orcein-picrothiazin and Masson's trichrome.
A few Aschoff bodies were found in the myocardium; the lungs contained lesions that are
considered typical for rheumatic pneumonitis and for the sequelae of mitral stenosis. In
one of the blocks cut from the lungs the islet of tissue was found (Figs. 1-3) that is the
subject of this paper. It was present in 6 additional sections (each? microns thick), although
in 3 of these the fragment of tissue was very small. The islet of tissue lay inside the lung
parenchyma, directly beneath the pleura. Its largest diameters were 500 by 500 microns.
It consisted almost exclusively of large cells which measured up to 30 microns. These cells
contained a nucleus, generally oval, having finely granular chromatin and one or sometimes two nucleoli. There were a ver}' few binucleate cells. The c.ytoplasm stained pale
red with hematoxylin azophloxin and sometimes contained a small faintly basophilic area;
it also stained pale red with Masson's trichrome and red with Heidenhain's azan stain. A
few cells contained one or two small vacuoles. The contours of the cells were always sharply
delimited. Apart from the large cells there were a few smaller elements and a few leukocytes. No mitoses were observed. In one of the sections a thin-walled wide blood vessel
was seen between the cells. In the periphery of the islet the large cells were seen to branch
out for a very short distance along the alveolar septums. In what was probably a tangential
section of the islet, the large cells were seen surrounding a group of "heart-failure" cells.
The connective tissue stains showed that each cell was surrounded by very thin fibers. In
the section stained with orcein and picrothiazin a peculiar pattern was observed: The island
was divided in groups of cells by a kind of septum composed of thin bundles of collagen
between which fragments of elastic fibers were present. In the same section there was a
small artery with a thickened intima in close contact with the large cells. A few of these
cells appeared to be tying inside the elastica interna of the vessel. Unfortunately the lack
of serial sections rendered it impossible to decide whether this was real or only apparent.
DISCUSSION
In my evaluation of the histologic findings I faced the same problems as
Park. 8 It was obvious at once that the tissue in question did not resemble anything which I had previously observed in normal or diseased lungs; on the other
hand, there was strong resemblance to decidua. In the other sections from the
same block and in those cut from the other blocks of pulmonary tissue nothing
similar was found. The large cells composing the islet were quite different from
the swollen alveolar "epithelial" cells5 or Nischenzellen1 which were numerous
nor did they resemble alveolar macrophages. The individual cells were all surrounded by connective tissue fibers; this does not occur with metaplastic bronchial epithelium. Comparison with syncytiotrophoblast and cytotrophoblast
convinced me that the large cells did not belong to these tissues. It must therefore be considered probable that the island of tissue was decidual in nature.
As already stated, W. W. Park 8 regards transport from the maternal part of
the placenta by way of the bloodstream as the most likely origin of the decidual tissue in his case. As regards an eventual origin from a pre-existing focus of
endometriosis, it must be observed that since glands are usually absent7 in intraabdominal ectopic decidua, which is generally observed in locations quite similar
to those in which endometrial islands have been found, the absence of glands in
our case does not necessarily argue against the endometrial origin of the decidualike tissue that was found by Park and by me. Hobbs and Bortnick4 succeeded in
establishing endometrium in the lungs of rabbits by injecting the curettings
Jan.
1956
DECIDUA-LIKE TISSUE I N LUNG
51
from the uterus into the ear veins. In animals that were impregnated after the
injections with endometrium, the pulmonary implants, which often had disrupted the walls of the'blood vessels, showed decidual reaction. But in the lungs
of women tissue of the endometrial type has never been demonstrated. Hart's
case3 is probably one of pulmonary hamartoma or adenomatosis and the
case of Willis,10 which is discussed by Park, certainly does not resemble endometriosis. Other cases of alleged pulmonary endometriosis sometimes cited in the
literature rest only on flimsy evidence. This is true in the case of Schwartz9 who
suspected pulmonary endometriosis of the lung in a patient with pulmonary
tumor with endometriosis of the inguinal lymph nodes, but had no anatomic or
histologic confirmation of his suspicion. I therefore agree with Park in regarding the origin from endometriosis as improbable, but I feel it is impossible
as yet to take a definite position regarding the question whether it has arisen
through metaplasia or transportation to the lung via the bloodstream.
SUMMARY
A small focus of tissue, probable decidua, was found in the lung of a 24-year-old
woman who died in the fourth month of pregnancy. No conclusion could be
reached as regards its origin.
SUMMA1UO I N
INTEKLINGUA
TJn parve loco de histos, probabilemente decidua, esseva trovate in le pulmone
de un femina de 24 annos qui moriva in le quarte mense de pregnantia. Nulle
conclusion in re le problema de su origine poteva esser attingite.
REFERENCES
1. BARGMANN, W.: Histologic a n d mikroskopische Anatomic cles Menschen. Vol. 2. Orgune
und Systeme. S t u t t g a r t : Georg Thieme Verlag, 1951, p p . 288, 2S9.
2. B U N G E L E R , W., AND F L E U R Y S I L V E I R A , D . : Consideracoes sobre a p a t o g e n i a das endo-
metrioses (a proposito do tres casos de endometriose externa). Arq. eir. clfn. e
exper., 3 : 169-187, 1939. [Cited by W. W. Park 8 ]
3. H A R T , C.: Histologisch henigne Mctastasen vom Ban eines Adenomyoms 22 J a h r e naeh
Exstirpation einos Tumors der Geuitalien. Frankfurt. Ztschr. P a t h . , 10: 78-90, 1912.
4. H O B B S , J . E . , AND BORTNICK, A. R . : E n d o m e t r i o s i s of t h e lungs. An experimental and
clinical study. Am. J . Obst. & G v n e c , 40: 832-843 1940.
5. M I L L E R , W. S.: The Lung. Springfield, Illinois: Charles C Thomas, 1937, p p . 56-64.
6. NICHOLSON, H . : Endometriosis of pleura. Thorax, 6: 75-81, 1951. [Cited by Park."]
7. NOVAK, E . : Gynecologic and Obstetric Pathology with Clinical & Endocrine Relations. E d . 3." Philadelphia: W. B . Saunders Co.; 1952, p . 155.
8. PARK, W. W.: T h e occurrence of decidual tissue within t h e lung: report of a case.
J. P a t h . & Bad,., 57: 563-570, 1954.
9. SCHWARTZ, O. H . : Discussion of "Endometriosis. A clinical and surgical review,"
by V. S. Counsellor. Am. J. Obst. & G v n e c , 36: 887-S88, 1938.
10. W I L L I S , R. A.: Pathology of T u m o u r s . E d . 2. London: B u t t e r w o r t h & C o . , 1953,
pp. 542, 543.