Baylor University Medical Center Proceedings January 2014, Volume 27, Number 1 | Page 28

a

b

Figure 1. The leiomyoma in patient 1 (a) displays interweaving fascicles of bland spindle cells with minimal to no cytologic
atypia (hematoxylin and eosin, ×200) and (b) has a diffusely positive stain for smooth muscle actin by immunohistochemistry,
classifying the tumor as a leiomyoma (immunohistochemical stain, ×200).

a

b

Figure 2. The leiomyosarcoma in patient 2 displays (a) diffuse nuclear pleomorphism with hyperchromatic, enlarged, and
atypical nuclei (hematoxylin and eosin, ×400) and (b) increased mitotic activity (up to 16 mitoses per 10 high-power fields
with atypical forms) (hematoxylin and eosin, ×200).

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Baylor University Medical Center Proceedings

It measured 2.5 cm and was
composed of tan-pink, soft
tissue. On microscopy, sections showed interlacing fascicles of spindled cells with
diffuse pleomorphism (Figure 2a), increased mitotic
activity (up to 16 mitoses
per 10 HPF with atypical
forms) (Figure 2b), and a focally infiltrative border. The
combination of these three
features was sufficient for
the diagnosis of leiomyosarcoma. Immunohistochemical stains for smooth muscle
actin and desmin highlighted the smooth muscle cells,
confirming the diagnosis of
leiomyosarcoma. The neoplasm was present at the surgical margin, and additional
therapy was recommended.
The clinician was contacted
to discuss the unexpected results and the significance of
a positive surgical margin,
which expedited the referral
to a gynecologic oncologist
for radical vulvectomy. Radical excision was performed
and no residual disease was
identified.
DISCUSSION
We present two cases
of vulvar smooth muscle
tumors that clinically mimicked Bartholin gland cysts.
These cases suggest that a biopsy should be performed,
rather than a drainage procedure,