Keywords
osteosarcoma - paratestis - calcification - spermatic cord - orchidectomy
Introduction
Extraosseous osteosarcoma (EOO), also known as soft tissue osteosarcoma, refers to
osteosarcoma occurring in soft tissue rather than bone. EOOs are uncommon, accounting
for only 4% of all osteosarcomas and 1% of soft tissue sarcomas.[1] Osteosarcoma arising from the testis, its supporting structures, that is, paratestis
or spermatic cord are exceedingly rare, with only 11 published English language reports
to date. In this report, we present a 73-year-old male presenting with left hemiscrotal
swelling, noted to have extensive amorphous calcification on imaging. Extirpative
pathology revealed primary paratesticular osteosarcoma. We also review published literature
with particular emphasis on imaging characteristics.
Case History
A 73-year-old patient presented with progressively enlarging left hemiscrotal mass
of 2 months duration. He denied history of trauma. Physical examination revealed a
15 cm bony hard mass in the left hemiscrotum infiltrating overlying skin. The left
testis was palpable separately at the inferior pole of the mass. Contralateral testis
was normal. Physical examination was otherwise unremarkable. Serum tumor markers (alpha
fetoprotein, beta-human chorionic gonadotropin and lactate dehydrogenase) were normal.
Ultrasonogram of the scrotum revealed a 10 cm mass with heterogenous echotexture and
multiple calcifications. Computed tomography (CT) revealed an ill-defined heterogeneously
enhancing mass with extensive amorphous intratumoral calcifications ([Fig. 1]). Both testes were noted separate from the mass and appeared normal. Metastatic
evaluation was negative. With a provisional diagnosis of malignancy, we performed
a metastatic evaluation, including a CT of the chest, abdomen, and pelvis, which was
negative.
Fig. 1 Computed tomographic images showing a large left paratesticular tumor with extensive
amorphous calcification. (A) Cross-sectional imaging, (B) sagittal image, and (C) coronal image through the tumor.
He underwent left high inguinal orchidectomy with en bloc hemiscrotectomy. Intraoperatively,
a discrete bony hard swelling, with the left testis adherent to its lower pole, was
noted. Gross pathology showed a 16.5 × 10 × 7.8 cm variegated tumor adjacent to the
testis, with cut surface showing solid and cystic areas. Calcified areas and necrosis
were also seen. Histology revealed spindle to polyhedral cells with scant eosinophilic
cytoplasm and hyperchromatic nuclei, with 14 mitoses per 10 high power field. Foci
of osteoid formation, calcification, and osteoclast-like multinucleated giant cells
were also noted ([Fig. 2]), suggesting a diagnosis of high-grade osteosarcoma arising from the paratestis.
This was corroborated on immunohistochemistry, which was positive for vimentin, variable
positivity for CD 99, and negative for SATB2, S100, desmin, CD34, and keratin.
Fig. 2 Histopathology. (A) Sheets of tumor cells with intervening osteoid matrix undergoing focal mineralization
(hematoxylin and eosin [H&E 100X]). (B) H&E 200X. (C) Tumor cells with hyperchromatic pleomorphic nuclei with adjacent osteoid and chondroid
matrix (H&E 200X). (D) Spindle-shaped tumor cells with hyperchromatic, pleomorphic nuclei with intervening
osteoid matrix following decalcification (H&E 200X).
After discussion in a multidisciplinary tumor board, considering the lack of evidence
for benefit of adjuvant therapy in localized disease, the patient was advised surveillance.
He remains disease free at 8 months of follow-up.
Discussion
EOOs are rare malignant mesenchymal neoplasms that produce osteoid, bone, and occasionally
cartilage. To be characterized as EOO, these tumors must (i) have a unified sarcoma
pattern (excluding mixed malignant mesenchymal tumor), (ii) produce bone-like and/or
cartilage matrix, (iii) be primarily located in soft tissues without skeletal attachment,
and (iv) a metastasis from a primary skeletal osteosarcoma elsewhere must be excluded.[1] The soft tissues of the lower followed by the upper extremity are most commonly
affected, and visceral involvement is rare. To the best of our knowledge, only 11
published reports in English language, of EOO of the testis, paratestis, or spermatic
cord exist ([Table 1]).
Table 1
Summary of published reports of testicular, paratesticular, and spermatic cord osteosarcoma
|
Study
|
Year
|
Age at presentation (years)
|
Primary organ of origin
|
Time to presentation (weeks)
|
Tumor LTD (cm)
|
Calcification on Imaging
|
Treatment
|
Adjuvant therapy
|
Outcome
|
Follow-up duration (months)
|
|
1
|
Mathew et al[2]
|
1981
|
73
|
Testis
|
8
|
3.5
|
NA
|
Orchidectomy
|
None
|
No recurrence
|
2.5
|
|
2
|
Zukerberg et al[3]
|
1990
|
30
|
Testis
|
52
|
6.0
|
NA
|
High inguinal orchidectomy
|
None
|
No recurrence
|
66
|
|
3
|
Lee et al[4]
|
2004
|
78
|
Testis
|
2
|
4.0
|
Calcified mass
|
High inguinal orchidectomy with RPLND
|
None
|
No recurrence
|
44
|
|
4
|
Tazi et al[5]
|
2006
|
60
|
Testis
|
16
|
12.0
|
Calcified mass
|
High inguinal orchidectomy
|
None
|
No recurrence
|
16
|
|
5
|
Resorlu et al[6]
|
2018
|
63
|
Testis
|
NA
|
16.0
|
NA
|
High inguinal orchidectomy
|
None
|
No recurrence
|
12
|
|
6
|
Al-Masri et al10
|
2007
|
52
|
Paratestis
|
16
|
17.0
|
NA
|
High inguinal orchidectomy
|
Adjuvant cisplatin, doxorubicin, and methotrexate
|
Expired due to retroperitoneal metastasis
|
6
|
|
7
|
Hong et al4
|
2012
|
52
|
Paratestis
|
52
|
6.5
|
Calcified mass
|
High inguinal orchidectomy
|
None
|
No recurrence
|
9
|
|
8
|
Spirtos et al[7]
|
1991
|
55
|
Spermatic cord
|
1
|
4.0
|
NA
|
High inguinal orchidectomy
|
None
|
No recurrence
|
24
|
|
9
|
Beiswanger et al5
|
1997
|
54
|
Spermatic cord
|
NA
|
7.0
|
Calcified mass
|
Wide local excision + high inguinal orchidectomy
|
None
|
No recurrence
|
9
|
|
10
|
Stella et al6
|
2007
|
59
|
Spermatic cord
|
260
|
25.0
|
Calcified mass
|
High inguinal orchidectomy
|
Inguinal and pelvic radiation (60Gy)
|
Expired due to lung metastasis at 9 years
|
132
|
|
11
|
Ugidos et al[11]
|
2010
|
62
|
Spermatic cord (liposarcoma + osteosarcoma)
|
NA
|
9.0
|
NA
|
High inguinal orchidectomy
|
None
|
No recurrence
|
8
|
Abbreviations: LTD, longest tumor dimension; NA, not available; RPLND, retroperitoneal
lymph node dissection.
EOO is hypothesized to arise from neoplastic transformation of sequestered primitive
mesenchymal cells or embryonic osteogenic tissue. In the testis, EOO must be distinguished
from sarcomatous transformation of germ cell tumors by excluding the presence of the
later in the resected specimen by meticulous pathologic examination, as was performed
in our case.
Based on the available data, common clinical presentation in the fourth to eight decades
of life, with a large, hard, hemiscrotal or groin mass, that developed over the course
of a few weeks to months ([Table 1]).
No pathognomic imaging features have been described to date. We reviewed all published
reports, with particular attention to findings on imaging studies. At presentation,
the tumor tends to be large with longest tumor diameter ranging between 3.5 and 25.0 cm
([Table 1]). Modest heterogenous enhancement is usually observed. Imaging is often remarkable
for extensive amorphous intratumoral calcification. This likely results from ossification
by osteosarcoma tumor cells. Although observed in previously published reports, these
unique imaging finding have not been not emphasised.[4]
[5]
[6]
[7]
[8] Calcification may occur in other testicular tumors such as nonseminomatous germ
cell tumors, particularly teratomas, and nongerm cell tumors such as large-cell calcifying
Sertoli cell tumor. However, this is usually focal and/or heterogenous and not as
pronounced as seen in osteosarcoma.[10]
[12] Calcification may also be noted in long-standing hydrocele or hematocele, in which
case it is usually peripheral and shell like.[13]
Unlike EOO at other sites which commonly present with metastatic disease,[1] majority of reported EOO arising from testis, paratestis or spermatic cord have
presented with localized disease. As with our patient, surgical resection, comprising
high inguinal orchidectomy with wide local excision of the tumor has been the mainstay
of management in most reports. Due to rarity of disease, the value of adjuvant chemotherapy,
radiation, or prophylactic retroperitoneal lymphadenectomy in localized disease remains
unknown. However, despite the lack of any adjuvant treatment, regional or metastatic
recurrence has been reported in only two instances,[9]
[14] suggesting a favorable prognosis in majority of patients with localized disease.
Conclusion
Although EOOs of testis, paratestis, or spermatic cord are exceedingly rare, they
should be included in the differential diagnosis of a male in the fourth to eight
decades of life presenting with a hard hemiscrotal or groin mass with extensive amorphous
intra-tumoral calcification on imaging. Surgical resection remains the mainstay of
management.
