*From the Department of Thoracic Surgery (Drs. Hasegawa and Inui), the Department of Pulmonology (Dr. Kamakari), and the Department of Orthopedic Surgery (Drs. Kotoura and Suzuki), Nagahama City Hospital, Nagahama, Japan; and the Department of Pathology (Dr. Fukumoto), Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.
Correspondence to: Seiki Hasegawa, MD, Department of Thoracic Surgery, Kyoto University Hospital, 53 Shogoin, Kyoto 606-8397, Japan; e-mail: email@example.com
A 29-year-old woman with an unusual form of pulmonary metastasis
from epithelioid sarcoma of the right forearm is presented. Since she
manifested left pneumothorax due to metastatic pulmonary cyst 7 years
ago, the only metastatic manifestation has been the presence of
bilateral multiple thin-walled pulmonary cysts; no other types of
pulmonary lesions, such as nodules, cavitary lesions with thick or
irregular walls, or extrapulmonary metastases, have been found.
Pathologic studies revealed metastatic proliferation of sarcoma cells
in the wall of the pulmonary cysts and infiltration of malignant cells
inside the microscopic cavitary metastases surrounded by normal lung
pulmonary lesions caused by metastasis of soft tissue sarcoma are rare.
When accompanied by multiple pulmonary nodules, such lesions can be
easily identified as possible metastases from an unidentified primary
tumor. However, when a pulmonary cyst is not accompanied by pulmonary
nodules or a noticeable primary lesion, it may not be readily
identified as a pulmonary metastasis.
We describe a 7-year follow-up of a patient in whom spontaneous
pneumothorax and multiple pulmonary cysts were the initial clinical
manifestations of epithelioid sarcoma of the forearm. Detailed serial
histologic studies revealed the possible mechanism by which the
malignant cysts developed.
A 29-year-old Japanese woman was admitted to Nagahama
City Hospital in June 1996 because of recurrent left pneumothorax. She
had several episodes of pneumothorax in both lungs. She had undergone
left thoracotomy in November 1991 and right thoracotomy in December
1993, and the histologic diagnosis of the resected lung tissue was
pulmonary bulla with metaplasia of the lining cells in all instances.
Chest CT on admission revealed bilateral pulmonary thin-walled cysts
measuring up to 2.0 cm in diameter. Results of physical and laboratory
examinations were unremarkable, except for a tumor on the right
forearm. The patient underwent partial resection of the left S10
segment, which contained several subpleural bullae. No other
intrapulmonary or pleural lesions were found during surgery. Although
pulmonary bulla with inflammatory reaction was the histologic
diagnosis, pathologists could not rule out mesothelioma or other
malignant diseases of the lung, because the lining cells of the cyst
wall showed atypia.
After completion of the treatment for left pneumothorax, a
detailed examination of the tumor on the right forearm was performed.
The patient had noticed (1) slight but progressive disturbance in
extension of the right middle and ring fingers since 1986 and (2) a
small nodule on her right palm since 1991. Radiologic studies revealed
a longitudinal mass located on the ulnar side of her distal forearm
measuring 2 to 4 cm in diameter and 15 cm in length, and a small nodule
on the medial-distal side of the right upper arm measuring 1 cm in
diameter. A biopsy led to a pathologic diagnosis of epithelioid sarcoma
of the right forearm and metastasis to the regional lymph nodes.
A detailed histologic reassessment of lung specimens obtained in
1991, 1993, and 1996 was made. Pulmonary tissue was compared
with the tissue removed from the forearm, and they were similar. Thus
the cystic lesions in these specimens were diagnosed as metastases of
epithelioid sarcoma. Systemic screening with CT and MRI was performed,
but no other metastatic lesions were found. No abnormal uptake was
observed by whole-body scintigraphy with
99mTc-methylene diphosphonate and gallium citrate
Ga 67, and slight uptake was observed only in the right forearm tumor
with thallous chloride Tl 201.
The patient is currently well, her only symptom being motor disturbance
in the right upper extremity. Her laboratory results show no
abnormalities and there is no evidence of distant metastasis except to
Multiple pulmonary cysts with thin and smooth walls in both
lungs were observed by chest CT in June 1996 (Fig 1,
top, A). Most of these lesions were
intraparenchymal and a few were subpleural. Serial CT studies revealed
that these cystic lesions appeared where only normal lung parenchyma
had been seen in previous CT scans, and that they grew slowly (Fig 1,
bottom, B). No nodules, cavitary lesions with
thick or irregular walls, necrotic tissue in the cysts, pleural
lesions, or enlarged lymph nodes were found throughout the follow-up
The macroscopic features of the cysts in the resected lung were
consistent with those of pulmonary bullae. Light-microscopic studies
were performed on formalin-fixed, paraffin-embedded, and
hemotoxylin-eosin-stained samples. The walls of the cysts lacked lining
epithelium and consisted of a dense proliferation of large spindle
cells with eosinophilic cytoplasm (Fig 2
). Nuclear atypism of the tumor cells was prominent, but no mitoses were
observed. Both fresh and old hemorrhages, hemosiderin deposits, and
partial calcification were seen in the cyst walls. There were several
microscopic cavitary lesions surrounded by normal lung parenchyma, and
the walls of the cavities were lined with sarcoma cells (Fig 3
Pulmonary metastases of soft tissue sarcomas commonly take the
form of solid nodules. However, only 14 cases, including the present
case, of cystic pulmonary metastases from soft tissue sarcomas have
been reported. In four of these cases, thin-walled cysts were the only
manifestation of pulmonary metastases. The cases involved the following
patients: a 20-year-old woman with leiomyosarcoma of the uterus, a
19-year-old woman with leiomyosarcoma of the ankle, an 86-year-old man
with angiosarcoma of the scalp, and the 29-year-old woman of the
present study 1–10 (Table 1
There is confusion or overlapping concepts about excavating, cavitary,
and cystic pulmonary metastatic tumors. Excavating pulmonary metastasis
may be defined by the mechanism of its formation; it is
initially a solid mass and its air-filled cavity is formed after
discharge of the necrotic material inside. Therefore, such lesions
usually have a thick and irregular wall and are seen with other lesions
at various stages of excavation. A cystic pulmonary metastasis is a
thin-walled, bulla-like lesion with or without accompanying nodular
Three possible mechanisms for the development of malignant cysts have
been described9,11–12: (1) excavation of a nodular tumor
through discharge of the necrotic material inside, (2) infiltration of
malignant cells into the walls of a preexisting benign pulmonary bulla,
and (3) infiltration of malignant cells into the walls of air sacs
formed by cystic distension of small airways through the ball-valve
effect of the tumor. Involvement of the first mechanism in the present
case was ruled out because no nodules or thick-walled cavitary lesions
appeared during the 7-year follow-up period. The second mechanism was
also unlikely, because the consistent increase in the number of
pulmonary cysts could hardly be explained by a progressive
emphysematous change in the lungs of this young, nonsmoking woman. The
likelihood of the third mechanism is strengthened by the presence of
microscopic cavitary metastases; these lesions are considered to be an
early stage in the development of macroscopic thin-walled cysts. Thus
we conclude that the pathogenesis of the metastatic cysts in the
present case may have involved the third mechanism.
None of the patients had received previous chemotherapy
or radiation therapy. F = female; M = male.
Become a CHEST member and receive a FREE subscription as a benefit of membership.
Individuals can purchase this article on ScienceDirect.
Individuals can purchase a subscription to the journal.
Individuals can purchase a subscription to the journal or buy individual articles.
Learn more about membership or Purchase a Full Subscription.
Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.
Some tools below are only available to our subscribers or users with an online account.
Download citation file:
Web of Science® Times Cited: 21
Customize your page view by dragging & repositioning the boxes below.
Enter your username and email address. We'll send you a reminder to the email address on record.
Athens and Shibboleth are access management services that provide single sign-on to protected resources. They replace the multiple user names and passwords necessary to access subscription-based content with a single user name and password that can be entered once per session. It operates independently of a user's location or IP address. If your institution uses Athens or Shibboleth authentication, please contact your site administrator to receive your user name and password.