Table 1 Clinicopathologic and immunohistochemical features of Paratesticular rhabdomyomas.

From: Molecular assessment of paratesticular rhabdomyomas demonstrates recurrent findings, including a novel H3C2 p.K37I mutation

Case

Age

Size2

Laterality

Location

Histology

Cellularity

Mitoses

Entraps normal structures

Relevant positive IHC

Relevant negative IHC

11

27

7

Left

Epididymis

Sclerosing rhabdomyoma

~20%4

<1 per 10 hpf

Yes (fat)

Desmin, Myf4

MDM2, HMGA2

21

42

12

Left

Paratesticular, NOS

Sclerosing rhabdomyoma

~20%4

<1 per 10 hpf

No

Myosin, Desmin

None

3

40

4.5

Right

Spermatic cord

Adult-type rhabdomyoma

~30–40%

<1 per 10 hpf

Yes (nerves and fat)

Desmin, MyoD1

MDM2, CDK4

41

34

4.5

Left

Paratesticular, NOS

Sclerosing rhabdomyoma

~20%4

<1 per 10 hpf

Yes (fat)

Desmin, MyoD1

None

51

21

2.5

Right

Epididymis

Sclerosing rhabdomyoma

~20–30%

<1 per 10 hpf

No

Desmin

None

6

61

1.2

Left

Paratesticular, NOS

Cellular fetal-type rhabdomyoma

~40–50%

<1 per 10 hpf

No

Desmin, MyoD1

MDM2, CDK4

7

32

2.5

Right

Paratesticular, NOS

Sclerosing rhabdomyoma3

~50%

<1 per 10 hpf

No

Desmin, MyoD1

None

8

20

4.2

Left

Spermatic cord

Cellular fetal-type rhabdomyoma

~40%

<1 per 10 hpf

No

Desmin, MyoD1

None

9

72

7

Right

Paratesticular, NOS

Adult-type rhabdomyoma

~90%

<1 per 10 hpf

No

Desmin, MyoD1

None

10

25

2.2

Left

Paratesticular, NOS

Sclerosing rhabdomyoma

~30%

<1 per 10 hpf

No

NA

NA

111

20

2

Left

Spermatic cord

Sclerosing rhabdomyoma

~30–40%

<1 per 10 hpf

Yes (fat)

Desmin

None

121

19

7

Right

Epididymis

Sclerosing rhabdomyoma

~20%4

<1 per 10 hpf

Yes (fat)

Desmin, fast myosin

S100r

13

40

2.1

Right

Paratesticular, NOS

Sclerosing rhabdomyoma

~20%4

<1 per 10 hpf

Yes (fat)

NA

NA

14

25

2.7

Left

Paratesticular, NOS

Sclerosing rhabdomyoma

~20–30%

<1 per 10 hpf

Yes (fat)

NA

NA

151

24

4.5

Right

Epididymis

Sclerosing rhabdomyoma

~20%4

<1 per 10 hpf

No

Desmin, fast myosin

MDM2, CDK4

  1. hpf High-power field, IHC Immunohistochemistry, NOS Not otherwise specified.1These cases were previously included in a series published by Jo, VJ et al. (Am J Surg Pathol. 2013;37:1737-42). 2In centimeters. 3This case was reclassified as cellular fetal rhabdomyoma (see discussion).4This cellularity represents the target cellularity after tumor enrichment by manual dissection for DNA sequencing, but the true cellularity might be lower (~5–10%).
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