# Sex Cord-Gonadal Stromal Tumor of the Rete Testis

Authors: Kamran P. Sajadi; Rory R. Dalton; James A. Brown
Journal: Advances in Urology
 (2009)

---

## Abstract

A 34-year-old tetraplegic patient with suppurative epididymitis was found on follow-up examination and ultrasonography to have a testicular mass. The radical orchiectomy specimen contained an undifferentiated spindled sex cord-stromal tumor arising in the rete testis. Testicular sex cord-stromal tumors are far less common than germ cell neoplasms and are usually benign. The close relationship between sex cords and ductules of the rete testis during development provides the opportunity for these uncommon tumors to arise anatomically within the rete tesis. This undifferentiated sex cord-stromal tumor, occurring in a previously unreported location, is an example of an unusual lesion mimicking an intratesticular malignant neoplasm.


---

## Body

## 1. Introduction

Physicians
frequently encounter scrotal lesions which, despite a careful history, physical
examination, and sonography, remain an enigma. The finding of a discrete mass
in the testis requires surgical exploration to exclude a malignant neoplasm. We
present a patient whose radical orchiectomy revealed a sex cord-stromal tumor
arising within the rete testis, which to the best of our knowledge is a
previously unreported location for this uncommon tumor.


## 2. Case Presentation and Management

A
34-year-old man with C3-C4 tetraplegia presented with right hemiscrotal
swelling and purulent drainage from the scrotal skin. Physical examination
disclosed a firm right testis mass, a 2 cm scrotal fluctuance, and abscess
drainage through the skin at the dependent, posterior aspect of the right
hemiscrotum. The abscess had spontaneously opened and drained to a degree that
he did not need a former incision and drainage procedure. An ultrasound (Figure1) revealed an 8mm×8mm×6mm intratesticular mass with calcifications. He was
treated with ciprofloxacin. Six weeks later, the drainage had ceased and a
repeat ultrasound showed the testis mass was stable in size. Preoperative
alpha-fetoprotein (AFP), beta-human chorionic gonadotropin (hCG), lactate
dehydrogenase, chest X-ray were normal. The decision was made to obtain a CT of
the abdomen and pelvis after surgery depending on the pathology results. A
right radical orchiectomy was performed. His postoperative course was
remarkable only for a small inguinal hematoma which spontaneously drained and
resolved.Figure 1
Ultrasound of the right testis,
longitudinal view. A hypoechoic lesion (arrow) is seen in the posterior testis,
near the mediastinum testis.


## 3. Pathology

The
testicle measured 2.5 cm by 2.1 cm and the attached segment of spermatic cord
measured7.3cm×2.1cm×1.1cm. The epididymis was firm and slightly diffusely enlarged. A 0.9 cm
well-circumscribed, firm tan-white nodule was identified in the testicular
hilum (Figure 2). The remainder of the parenchyma of the testicle was
unremarkable.Figure 2
Bisected radical orchiectomy
specimen. The tumor can be seen as a smooth, round, pale lesion (arrow) at the
mediastinum testis.Microscopic
examination (Figure3, upper right and lower panels) revealed the nodule to be
comprised of a well-demarcated, nodular proliferation of bland spindle cells
within the mediastinum testis. No areas of tubule or cyst formation were identified. The
spindle cells surrounded unremarkable ductules of the rete testis. Neither
mitotic activity nor necrosis was present. Immunohistochemical stains for placental alkaline
phosphatase (PLAP), CD30, hCG, AFP, CD99, and caldesmon were negative. The
spindled cells were positive for vimentin, S-100, WT-1, and focally positive
for inhibin and pancytokeratin. Also present were acute and chronic
inflammation of the epididymis.(a) Closer view of gross specimen
demonstrating discrete white nodule which was firm. (b) A spindle cell
proliferation was intimately associated with unremarkable ductules within the
rete testis. (c) Higher power view
illustrating bland spindled cell proliferation without mitotic activity.
(a)(b)(c)


## 4. Discussion

Scrotal
lesions are a frequent diagnostic dilemma, and the underlying lesion may remain
undefined despite thorough clinical and radiographic investigation. The most
important consideration is an underlying testicular germ cell tumor. The close
proximity of paratesticular structures, including the rete testis, efferent
ductules, epididymis, vas deferens, spermatic cord, tunica, or vestigial
testicular appendages, may result in such lesions appearing to be intratesticular
on examination and ultrasound [1]. Many such lesions, therefore,
require radical orchiectomy to definitively rule out a germ cell neoplasm.The rete testis
develops from sex cords and the degenerating mesonephric duct and includes an intratesticular
portion (the tubulae rete and mediastinal rete) and an extratesticular portion
comprised of several vesicular structures (extratesticular bullae retis) which
form the efferent ductules [2]. As in this case, pathologic processes involving the rete testis may
mimic intratesticular germ cell neoplasms clinically and radiographically. Benign processes occurring in the rete
testis include epithelial hyperplasia, nodular proliferation of calcifying
connective tissue and cysts [3, 4]. Neoplasms occurring in the rete testis include the benign adenoma
(also known as benign papillary tumor, cystadenoma, papillary cystadenoma, and
adenofibroma) and carcinoma of the
rete testis [1, 4]. The
carcinoma of the rete—presumably
arising from the epithelium of the ductules—is rare and is
associated with a poor prognosis [1, 3]. Similar to the
confounding picture in this case, patients with adenocarcinoma of the rete
testis often present with pain, swelling, and induration resembling
epididymo-orchitis [3]. The close relationship during development
between the sex cords and the ductules of the rete testis provides the
opportunity for SCSTs to arise anatomically within the rete testis [1]. This is supported by the observation that microscopic foci of gonadal stroma
are occasionally incidental findings in the extratesticular region of
orchiectomy specimens removed for other reasons [1].Sex cord-stromal
tumors (SCSTs) represent
approximately 3% of testicular neoplasms and are rare outside the testicle [5]. In the testis, approximately one-half of sex cord-stromal tumors are Leydig
cell tumors, with the remainder including Sertoli cell tumors, Granulosa cell
tumors, mixed tumors, and tumors of uncertain or indeterminate differentiation
(unclassified sex or undifferentiated SCSTs) [6]. Undifferentiated
SCSTs are comprised of elements which cannot, at the light microscopic level,
be characterized as having Sertoli, Leydig, or Granulosa cell differentiation.
Unclassified SCSTs with a predominance of spindle cells have been described in
the testis proper [7]. In these cases, immunohistochemistry is useful
to establish that the spindle cell proliferation is of sex cord-stromal origin.
In a series by Renshaw et al., reactivity for S-100 and smooth muscle actin was
consistently present [7]. Interestingly, three of the four unclassified
SCSTs they identified arose adjacent to the rete testis. Inhibin is specific
for SCSTs and was uniformly reactive in a series of unclassified SCSTs reported
by Compérat et al. [6]. In that series, 95% of all SCSTs identified
showed immunoreactivity to Vimentin, CD99, and/or inhibin. The
immunohistochemical staining pattern in this case was consistent with a sex
cord-stromal tumor.The behavior and
prognosis of SCSTs is difficult to predict. As many as 80–90% of these
lesions behave in a benign fashion, but they cannot be differentiated from germ
cell tumors and their behavior cannot be predicted clinically or
sonographically [5]. Features associated with a malignant clinical
behavior include large size, invasive margins, vascular invasion, mitotic
activity, and necrosis [6, 7]. None of these features were present in
our patient, and this undifferentiated spindled SCST is expected to behave in a
benign manner.



---

*Source: 624173-2008-12-31.xml*