Case 108. Giant Lipoma of the Spermatic Cord

Clinical case. A 72-year-old patient who died from myocardial infarction. He has no prior history. The material corresponds to an autopsy finding.

Pathological findings. The specimen measures 22.5 × 8 cm in its maximum diameters. It is formed by the testicle, the epididymis, and 19 cm of spermatic cord. An elongated 18 × 8-cm tumor stands out at the level of the spermatic cord. The tumor is well delimited and yellow. The cut surface has a uniform yellowish color without areas of fibrosis, necrosis, or hemorrhage. The tumor is formed by adult adipose cells of uniform morphology. It is interrupted by very thin conjunctive septa. It presents a scanty vascular network. Cells surround the spermatic cord and the deferent vessels. The tumor is externally covered by a capsule. The testicle presents focal atrophy of the seminiferous tubules. The epididymis shows no alterations.

Comments. The uniformity of the adipocytes, the lack of atypia, and the size of the tumor makes the diagnosis of giant lipoma of the spermatic cord easy. Lipoma is the most frequent tumor of the spermatic cord. There are some topics worth discussing about these tumors regarding definition, clinical and differential diagnosis. The lipoma of the spermatic cord is a tumor located in the cord that has no communication with the peritoneum, and this fact distinguishes it from the frequent abdominal fat herniation. Tumor cell proliferation occurs mainly in the spermatic compartment of the cord. Clinically, they are asymptomatic despite the large size they can reach. They are usually discovered in the intervention of a hernia. Whether the hernia can be facilitated by the lipoma itself if it causes dilation of the internal inguinal ring is still a matter or argument. Only half the cases are correctly diagnosed as lipomas with ultrasound, the rest were misdiagnosed as a hernia. The differential diagnosis, especially in large tumors, has to be done with atypical lipomatous tumors and well-differentiated liposarcomas, both of them locally aggressive tumors with a tendency to recur. In addition to cytology, immunohistochemistry is very useful as lipomas do not have MDM2 amplification on cytogenetic testing as do atypical lipomatous tumors or well-differentiated liposarcomas.

Case 109. Dedifferentiated Liposarcoma of the Spermatic Cord

Clinical case. A 78-year-old patient who presented with a tumor of several years of evolution in the right inguinal region. The serum levels of testicular tumor markers were negative.

Pathological findings. The specimen showed a 13 × 7.8 × 7.3-cm tumor of the spermatic cord. It has two areas with different colorations—one of them larger, yellowish, lobed, and the other one grayish with myxoid and hemorrhagic areas. The tumor is well delimited but not encapsulated. The delimitation with the testicle is crisp. The yellow part of the tumor is made up of adipose cells that simulate mature adipocytes in most of the fields, while in the rest there are abundant lipoblasts with variable fat accumulation. The second area of the tumor is formed by a proliferation of fusiform cells arranged in cross-linked bundles. These cells show moderate pleomorphism, prominent nucleoli, frequent eosinophilic cytoplasms, and abundant mitosis. The tumor often shows hyalinization areas. Focally, the fascicular structure is lost and there are frequent cells with one or several large nuclei. Most of the cells of this second tumor component express SMA and MDM2.

Comments. The macroscopic aspect suggests that there are two different tumors, both for the distinct separation and different color. Precisely this perfect separation is what characterizes the dedifferentiated liposarcomas. Histologically, the dedifferentiated liposarcoma is formed by a well-differentiated liposarcoma, and a nonlipogenic cellular spindle cell or low-to-high pleomorphic sarcoma. Among the most frequent of these, the following have been described: fibrosarcomas, myxofibrosarcomas, osteosarcomas, leiomyosarcomas, angiosarcomas, and undifferentiated pleomorphic sarcoma. In the case we are discussing, this second component was considered a moderately differentiated leiomyosarcoma. It is important to separate this variant from most liposarcomas since the prognosis is worse although in most cases the clinical course is very slow.

Case 110. Dedifferentiated Liposarcoma with Undifferentiated Pleomorphic Sarcoma (Malignant Fibrous Histiocytoma)

Clinical case. A 68-year-old patient who over the last year developed a painless left inguinal. The ultrasonography revealed a 16 × 12 × 10-cm solid mass in the spermatic cord; it is hypoechoic with isolated hyperechoic areas inside. The mass is well delimited and separated from the testicle.

Pathological finding. The 22 × 12 × 12-cm surgical specimen includes the testicle and a voluminous tumor in the spermatic cord. At the opening of the tunica vaginalis, a testicle of diminished size (3 × 2 × 2 cm) and a slight hydrocele are observed. The tumor is whitish-gray and firm in consistency. In several areas, it reaches the vicinity of the margin of the surgical resection. In the different sections, there is a tendency to lobulation with areas of necrosis and hemorrhage. Histologically, most of the tumor presents an irregular cell disposition, highlighting the fusocellular and hemangiopericytoid patterns focally. There is a great cellular diversity, from spindle cells with elongated nuclei to round cells and multinucleated cells. Some lymphocytes are observed between the cells. The number of mitoses is high. In the spindle cell areas, small groups of lipoblasts are observed. The tumor cells are negative for smooth muscle markers (actin, desmin), skeletal muscle markers (desmin, MyoD1, and myogenin), markers for neural differentiation (S100 and neurofilaments), and vascular markers (CD31, CD34). Only lipoblasts are positive for S100. Most of the cells express MDM2, CD68, Factor XIII, and alpha-1 antitrypsin.

Comments. This tumor was diagnosed more than a decade ago as a high-grade pleomorphic sarcoma highly suggestive of malignant fibrohistiocytoma based on the absence of expression of markers of other cell lines, marked atypia, and positivity for histiocytic markers (CD68, Factor XIII, and alpha-1 antitrypsin). In the recent histological review, groups of small lipoblasts and slight atypia were observed to have gone unnoticed in the spindle cell areas. At the same time, MDM2 was made and surprisingly most of the nuclei appeared intensely stained. So, the tumor was now considered a dedifferentiated liposarcoma in which the sarcomatous zone shows differentiation from malignant histiocytoma. This is the usual history of most malignant fibrohistiocytomas of the spermatic cord. The tumor also shows another peculiarity, the marked hemangiopericytoma-like vascular pattern of some areas, which although may be present in undifferentiated pleomorphic sarcoma, here is very patent.

Case 111. Unusual Dedifferentiated Liposarcoma (Well-Differentiated Liposarcoma with Pleomorphic Liposarcoma) of the Spermatic Cord

Clinical case. A 74-year-old patient with a voluminous painless inguinal mass that has been growing for more than 1 year. Radical orchiectomy including 13 cm of the spermatic cord was performed.

Pathological findings. The surgical specimen weighs 79 g and measures 18 cm in length with a maximum width of 8 cm. An atrophic testicle is identified at one end. Most of the specimen corresponds to a tumor of the spermatic cord. The tumor has two different nodules, one whitish-yellow in the upper part and the other one grayish in the lower part. The delimitation between the two parts is clear. The tumor is well defined but contacts the resection margins. Histologically, the upper nodule is constituted by a proliferation of adult adipose cells with slight nuclear atypia and isolated lipoblasts. The inferior nodule is formed by a proliferation of atypical lipoblasts that are distributed forming clusters or are dispersed in a stroma that varies from myxoid to highly hyalinized. These cells expressed MDM2.

Comments. The presence of an abrupt transition to a pleomorphic liposarcoma in a well-differentiated liposarcoma is exceptional. It is considered a variant of dedifferentiated liposarcoma in which what has happened is a homologous lipoblastic differentiation. This diagnosis is supported by the presence of giant marker ring chromosomes and MDM2 amplification in pleomorphic areas. Most of these tumors have been reported in the retroperitoneum and only isolated cases in the scrotum, buttock, and abdominal cavity. The average age of patients is 59 years (range: 35–84 years).

Case 112. Leiomyoma of the Epididymis with Indolent B-Lymphoblastic Proliferation

Clinical case. A 69-year-old patient who consulted for an increase in the left hemiscrotum over the last 5 years. The ultrasonography showed an extratesticular nodule in the lower pole of the left testicle. It was solid, lobulated, hypoechoic, and hypervascularized, measuring 1 × 1.9 × 1.6 cm.

Pathological findings. The tumor is composed of fusiform cells arranged in bundles in all spatial directions. The cells have an elongated nucleus with blunt ends and lack of atypia. Mitoses are exceptional (<1/50 HPF). The tumor presents an infiltrate of lymphocytes both in perivascular situation and among the tumor cells. This infiltrate is preferably peripheral. The tumor shows areas of necrosis and others with myxoid degeneration. Tumor cells are SMA-positive and the lymphoid infiltrates express CD20 and CD79a.

Comments. This leiomyoma has the following peculiarities: location in the tail of the epididymis, areas of necrosis, areas of myxoid degeneration, and infiltrates of lymphocytes, preferably B. Leiomyoma of the epididymis is a rare tumor whose incidence is much lower than that of the adenomatoid tumor. Less than 200 cases have been reported. Despite the presence of areas of necrosis, the good peripheral delimitation, the low rate of cell proliferation, and the absence of cellular atypia differentiate it from well-differentiated leiomyosarcomas. Myxoid areas are not frequent in leiomyomas; they are more characteristic of smooth muscle hamartomas, which also occur preferentially in the tail of the epididymis, and with which a differential diagnosis must be made. B lymphocyte infiltrates are a very rare finding that have only been described in some uterine leiomyomas. They are small cells with a low number of mitoses that besides being CD20-positive also express CD79a and Pax5. The small B cells coexpress TdT and Ki67. The meaning of this is unknown. A primary diffuse large B-cell lymphoma has been reported to be originated in a uterine leiomyoma.

Case 113. Leiomyosarcoma of the Epididymis

Clinical case. A 51-year-old patient who consulted due to a slow-growing scrotal mass over the last months. The ultrasound showed a 5 × 3 × 3-cm paratesticular mass located in the right epididymis. The abdominal CT scan showed no alterations. Testicular tumor markers were negative. An orchidoepididymectomy was performed.

Pathological findings. The tumor is located in the epididymis into which it infiltrates focally rejecting the testicle. It has a lobed surface and is partially encapsulated. When cut, the surface is whitish with fasciculate areas, small hemorrhages, and myxoid areas. It is constituted by bundles of spindle cells that are arranged in interlaced fascicles; some of them are seen sectioned longitudinally, and others transversely or obliquely. The cells have elongated nuclei with blunt ends and eosinophilic and fibrillar cytoplasm. There is a moderate anisocytosis and, in general, a low cellular pleomorphism. The number of mitoses does not exceed 2/10 HPF. No necrotic areas are observed. The cells express the following immunohistochemical markers: SMA, vimentin, and calponin.

Comments. The cytological and immunohistochemical characteristics are typical of a well-differentiated leiomyosarcoma. Paratesticular leiomyosarcomas affect patients between 34 and 86 years (mean: 62). About 40% of them are located in the testicular tunica, 40% in the spermatic cord, 10% in the scrotal wall, and 10% in the epididymis. They are usually classified in three grades, most of them being low grade. Metastases occur both by the lymphatic pathway to retroperitoneal lymph nodes and via the blood vessels to the lung.

The most frequent differential diagnosis is posed with leiomyoma, inflammatory myofibroblastic tumor, neurinoma, and dedifferentiated liposarcoma and less frequently with fibrous and sarcomatoid mesothelioma, fusiform cell rhabdomyosarcoma, and undifferentiated pleomorphic sarcoma. Immunohistochemically, the leiomyosarcoma also expresses SMA, desmin, heavy caldesmon, and smooth muscle myosin heavy chain in many cases. Less specifically, some express low-weight cytokeratins (8 and 18), S100, CD34, and estrogen and progesterone receptors.

Case 114. Leiomyosarcoma of the Spermatic Cord

Clinical case. A 49-year-old patient who presented with a 6-month-long enlargement of the left testicle. On examination, a hard, paratesticular, painless mass, and a large hydrocele were observed. At the ultrasonography, the Doppler color revealed a solid, heterogeneous mass with increased vascularity. Serum levels of testicular tumor markers were negative.

Pathological finding. The surgical specimen consists of testicle, epididymis, and an 8-cm-long spermatic cord. It weighs 63 g and measures 11 × 5 × 4 cm. After opening the tunica vaginalis, a normal size testicle is observed. In continuity with the tail of the epididymis and in the spermatic cord an elongated tumor is located, encompassing the cord during a length of 5.6 cm, with 4.8 cm in its maximum thickness. The tumor is well delimited, but not encapsulated. Its consistency is firm. The section has a whitish color and a fasciculate surface. It shows neither hemorrhagic nor necrotic areas. Histologically, it is constituted by a proliferation of spindle cells that are arranged in interlacing bundles. Most cells have an elongated nucleus with blunt ends and an eosinophilic cytoplasm. Focally, coinciding with the presence of multinucleated cells with spherical nuclei, the fascicular arrangement is lost. The intercellular space is minimal except for hyalinized areas in which thick collagen bundles separate the cells. The presence of small lymphocytic infiltrates is frequent. The mitotic index is high. Most of the cells show intense immunostaining for SMA. The testicle has no other alterations than a marked tubular ectasia and the cystic transformation of the rete testis. The tail of the epididymis is in continuity with the tumor of the spermatic cord.

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