Sclerosing epithelioid fibrosarcoma (SEF) is a rare sarcoma of low-grade malignancy. There has been no report to describe the comparison of histological features of SEF between primary and metastatic lesions in spite of high local recurrence rate. We report the histological changes and increasing Ki-67 labeling index of the primary and metastatic lesions of SEF. The patient was a 31-year-old man. At 18, a tumor in the abdominal wall was excised. At 23, the tumor recurred which was removed again. At 30, he was referred to our hospital because of swelling and pain in the chest. Histological examination of the chest wall tumor showed epithelioid cells arranged like alveolar pattern with dense collagen stroma. These findings were consistent with those of SEF. Abdominal and the rib tumors showed the same immunohistochemistrical expression. It is noteworthy that the tumor cells of the rib lesion showed increased cellularity, and its Ki-67 activity was higher as compared with the abdominal tumor, suggestive of progression of malignancy of SEF.
Sclerosing
epithelioid fibrosarcoma (SEF) is a very rare sarcoma which occurs in the deep
musculature. Extensive English literature survey reveals that there have been
only fifteen reports so far. There is wide age of spectrum and median age is 45
and equal sex distribution [
It is first reported by Meis-Kindblom in 1995.
The author described SEF as a variant of fibrosarcoma simulating carcinoma. This
tumor is characterized by epithelioid cells arranged in nest and strands in highly
sclerosing matrix. SEF is a relatively low-grade fibrosarcoma histologically [
On the other hand, high rate of
recurrence and metastasis has been reported. Meis-Kindblom et al. reported that local recurrence
occurred in 53% and metastasis occurred in 43%. Their interval of metastasis
was 4.7 to 14 years. In some other cases, uncontrollable recurrence and
metastasis occurred after uneventful some years. They stated that SEF is a clinically
malignant sarcoma [
There is no report about the comparison
of histological characteristics of SEF between primary and metastatic lesions
in spite of high local recurrence rate. In some case reports, the biopsy from the
metastasis lesion was performed, and the pathology was consistent with the primary
lesion [
A 30-year-old
man presented with 2-year history of bump and pain in his left chest. In 1995,
the soft tissue tumor of abdominal wall was excised. In 2000, the recurrent tumor
was excised again. In January of 2007, he was referred to our hospital. There
was tenderness in the left chest. Radiological examination revealed a lesion
with bone destruction in the left 6th rib (Figure
(a) Plain radiogram showing bone destruction of the rib (arrow). (b) Bone scintigram showing increased spots in the bilateral humerus and the left rib (arrow). (c) Plain radiogram of the left humerus showing an osteolytic lesion (arrow). (d) T1 weighted magnetic resonance imaging showing gadolinium enhancement (arrow).
Retrospective histological
examination of the specimen removed in 1995 revealed that the lesion was composed
of many spindle cells admixed with abundant collagen matrix (Figure
the specimen of the abdominal tumor excised in 1995 showing abundant collagen proliferation (a) and alveolar pattern (b).
The tumor removed from abdominal
wall in 2000. There was richness in abundant collagen. The features of the
tumor were similar to those of the previous surgery specimen. However, this
tumor showed increased cellularity. In this specimen, epithelioid cells were more dominant than spindle
cells, and the epithelioid cells were arranged in alveolar pattern (Figure
The specimen of the abdominal tumor excised in 2000 showing epithelioid cells arranged in an alveolar pattern, too.
To confirm the diagnosis, excisional
biopsy of the 6th rib was performed. Macroscopically, the bone marrow was occupied
by a white solid tumor. Microscopically, the specimen was composed of dysplastic
cells in the hyalinized stroma. These cells were arranged in epithelioid and
alveolar patterns too. In contrast to the primary lesion, this lesion was
characterized by much higher cellularity, high nuclear/cell rate, and more prominent
nuclear polymorphism (Figure
The specimen of the rib excised in 2007 showing cellular atypia and prominent nuclear pleomorphism.
Immunohistochemical examination
revealed vimentin-positive cells. Although it was focal, tumor cells were
positive for HHF-35. CD99 had a weak immunostaining pattern. Tumor cells were
negative for
Ki-67 labeling indices were
Ki-67 staining of the specimen resected in 1995. There are few Ki-67 positive cells. Ki-67 labeling index was 7 to 8%.
The specimen resected in 2000. There were more Ki-67 positive cells than Figure
The specimen resected in 2007. More cells were stained by Ki-67. Ki-67 labeling index was 60%.
In February 2007, pathological fracture occurred in the left humeral shaft. Since it was a metastatic lesion, chemotherapy using ifosfamide and adriamycin was performed. However, this chemotherapy was discontinued because of acute myocardial infarction. Since the tumor size is increasing, the patient was treated by radiation therapy to the left humerus. After that, he hoped the second opinion, so he was referred to another hospital.
SEF is characterized by uniform, small, and round
to ovoid epithelioid cells with clear cytoplasm arranged in distinct nest and
cords, embedded in a hyalinized fibrous stroma. This histology stimulates
infiltrating carcinoma. In contrast, there are hypocellular and fibromatous
areas which contain spindle cells and abundant collagen, simulating fibroma [
In addition, the SEF is characterized
by a range of other morphologic appearance. Meis-Kindblom et al. described that
there were myxoid zones with cyst formation in the SEF and that more cellular
myxoid zones stimulated myxoid fibrosarcoma [
In our case, polymorphic epithelioid
cells arrange in nest and strand, and there is much abundant collagen and
fibroblasts. There is nuclear polymorphism too. It is consistent with
Meis-Kindblom's report [
Meis-Kindblom described that in most fibrosarcoma,
immunohistochemical staining was of limited value although it was useful for
excluding other lesions [
In the cases which were difficult to
diagnose, ultrastructural examination was performed and the features displayed
the features of fibroblasts [
In our case, vimentin was diffusely positive.
Cytokeratin and
Ki-67 is a nuclear antigen which is
expressed in late G1, S, M, G2 growth phases. In other words, Ki-67 is
expressed only when mitosis occur. There is a correlation between high Ki-67
labeling index, especially, more than 20%, and poor clinical diagnosis in soft
tissue sarcoma [
In our case, Ki-67 labeling index has changed among three specimens. The abdominal tumor resected in 1995 showed 7 to 8% labeling index. The abdominal tumor resected in 2000 showed 20%, the bone tumor of the rib showed 60% Ki-67 labeling index, respectively. We concluded that malignancy grade has increased.
Clinically, in many cases of SEF
local recurrence [
In our case, metastasis has occurred after 12 years. This feature is consistent with these reports.