Clinico-radiological and pathological evaluation of extra testicular scrotal lesions

Abstract

Background:

Scrotal ultrasound, though reliable in distinguishing between intratesticular and extratesticular lesions and characterizing them as cystic and solid, cannot distinguish benign from malignant pathology. Although fine needle aspiration cytology (FNAC) has proved to be of great diagnostic importance in testicular lesions, its scope in extratesticular lesions is largely unexplored.

Aim:

To evaluate extratesticular scrotal lesions cytologically and compare it with their clinical, radiological, and histological findings.

Materials and Methods:

Sixty five patients with extratesticular scrotal lesions were assessed clinically, radiologically, and cytologically. Histopathology was done in 45 cases where surgical exploration was undertaken. All the data were then analyzed and correlated.

Results:

Extratesticular lesions accounted for 72.2% of the scrotal swellings. Of these, the epididymis is most commonly involved (61.5% cases) with the commonest type of lesion being cystic (49.3% cases). Ultrasonography preferably with color doppler is highly useful for the evaluation of the scrotum. Apart from distinguishing extratesticular from testicular and cystic from solid lesions, it has an important role in identifying individual lesions, thus reducing the list of differential diagnosis. Fine needle aspiration cytology contributed to a definitive diagnosis in 47.7% cases. It helps classify cystic masses on the basis of their contents and defines the etiology of chronic inflammatory lesions, apart from corroborating with the clinico-radiological diagnosis. Histological evaluation was possible only in cases where surgery was performed and helps further define the diagnosis.

Conclusion:

Fine needle aspiration cytology is essentially non-traumatic and easy to carry out and should be a technique of choice for the study of scrotal pathology, main advantage being avoidance of delays in diagnosis.

Introduction

The scrotum was earlier considered as an area of unaided clinical expertise. Nevertheless, the nature of some of the scrotal masses remains baffling.

Scrotal masses may be intratesticular or extratesticular, either solid or cystic. Most of the intratesticular masses should be considered malignant unless proved otherwise. Extratesticular cystic masses are almost certainly benign, whereas extratesticular solid masses have a malignant rate of 16%, which though being much lower than intratesticular masses, is high enough to be of concern.[1]

Scrotal ultrasonography (USG) has proved to be a highly reliable method to distinguish between intratesticular and extratesticular lesions and to characterize them as solid or cystic. However, it cannot reliably differentiate benign from malignant pathology.[2] The introduction of magnetic resonance imaging (MRI) and correlation with histopathology have helped to shorten the list of differential diagnoses and modify the management of the patients with extratesticular scrotal masses. Although fine needle aspiration cytology (FNAC) has proved to be of great diagnostic importance in testicular lesions, its scope in extratesticular lesions is largely unexplored. The aim of the present study is to evaluate the usefulness of FNAC as a diagnostic tool in the management of scrotal swellings, as well as to correlate the clinical, radiological, cytological and histopathological findings in different types of extratesticular scrotal lesions.

Materials and Methods

A total of 90 patients presented with scrotal swelling over a period of 1½ years in outpatient and inpatient departments of our hospital. Of these, 25 patients were excluded because a testicular pathology was detected after ultrasonographic evaluation. The remaining 65 cases (72.2%), comprising the study group, were studied prospectively and assessed clinically, radiologically, cytologically and histomorphologically. The data collected were tabulated, analyzed and correlated.

Gray-scale ultrasonography was done in all cases, accompanied by color doppler in the suspected cases of epididymitis, torsion and varicocele.

FNAC was done under sonographic guidance after confirmation of the extratesticular nature of swelling by ultrasound, by using a 23-gauge needle and a 10-mL disposable syringe. Cytospin smears were prepared from the aspirated fluid. After fixation, slides were stained with Papanicolaou or hematoxylin and eosin stains.

In 47 cases where surgical exploration and excision was undertaken, the histopathology was also done and the findings were correlated.

Results

Out of 65 patients, the epididymis was found to be involved in the maximum number of cases [40 cases (61.5%)], followed by the tunica vaginalis [17 cases (26.1%)], the spermatic cord and the scrotal wall [4 cases (6.2%) each].

The chief pathologies encountered were: Cystic lesions [32 cases (49.3%)], inflammatory lesions [28 cases (43.1%)] and tumor and tumor-like lesions [5 cases (7.6%)]. The sites of origin and causes of the various lesions are summarized in Table 1.

Table 1.

Distribution of cases of extratesticular swellings

The age of the patients ranged from 12 to 75 years, with the maximum number of patients [28 cases, (43.1%)] in the age group 21-30 years. The mean age at presentation was 32.1 years.

Scrotal pain or tenderness was the commonest symptom [37 cases, (56.9%)]. Scrotal swelling was the only complaint in 23 (35.4%) patients. In the remaining patients, there was a wide spectrum of additional complaints such as fever, general debility, urinary complaints, dragging sensation, trauma and infertility.

Eleven (16.9%) patients presented with acute scrotum, characterized by acute pain and swelling of scrotum with the duration of symptoms varying from 1 day to 1 week. They included 10 cases clinically diagnosed as acute epididymitis with or without orchitis and one case of pyocele. One case presenting as acute scrotum clinically but diagnosed as testicular torsion radiologically was excluded from the study group. The remaining 54 (83.1%) patients presented with long-standing symptoms, varying from weeks to months, even years. The clinical diagnoses were made based on the above symptoms, the commonest being chronic epididymitis [Table 2].

Table 2.

Clinical diagnosis

The extratesticular swellings were predominantly unilateral, while bilaterality was present in only 6 patients (9.2%). Swellings showed no predilection for any hemiscrotum, except for varicocele, where left-sided lesions predominated. All the 65 patients were scanned by USG and color doppler wherever possible. In addition to confirming the clinical diagnosis in all the other cases, USG evaluation led to a different diagnosis in 2 (3.1%) of the cases. These were a case of paratesticular neoplasm and a case of scrotal neoplasm, which were clinically diagnosed as chronic epididymis and sebaceous cyst, respectively. USG also provided additional information in 19 (29.2%) cases: 1 case diagnosed as acute epididymo-orchitis where inflammation was limited to the epididymis; 15 cases of fluid accumulation which were grouped into two categories: Simple fluid (hydrocele) with anechoic film in 12 cases and complex fluid (hematocele/pyocele) with internal echoes in 3 cases; 3 cases with the differential diagnosis of scrotal calcinosis and sebaceous cyst where calcified scrotal masses were seen, although a definitive diagnosis could not be made.

Cytological evaluation was attempted in all the patients with extratesticular scrotal swelling. FNAC was not done in four patients diagnosed to be varicocele, as clinical diagnosis and imaging findings in varicocele are essentially diagnostic.

Cytological evaluation done in the 56 (86.1%) patients was found to correlate with the clinico-radiological diagnosis [Table 3]. Cytology further added to the diagnosis in 31 cases (47.7%). For example, three cases diagnosed as complex hydrocele radiologically were differentiated into haematocele and pyocele. Cases of pyocele showed pus-like aspirate with predominant neutrophils. Cases of hematocele yielded bloody aspirate with smears showing blood or altered blood. FNAs from hydrocele yielded straw-colored fluid and scanty smears comprising squames, macrophages and mixed inflammatory cells.

Table 3.

Clinico-radiological and pathological correlation of extratesticular swellings

Twelve cases of cystic masses of epididymis were subclassified into epididymal cysts and spermatoceles on the basis of both the color of the fluid aspirated and the cell component. Epididymal cysts yielded clear, straw-colored fluid which comprised histiocytes, lymphocytes, neutrophils, at times histiocytic giant cells and squames. In cases of spermatocele, milky or turbid fluid was aspirated and showed numerous sperms, other spermatogenic cells, sertoli cells and histiocytes [Figure 1a and b].

Figure 1.

(a) Epididymal cyst/spermatocele. Anechoic cyst in the head of epididymis; (b) Spermatocele. Smear shows dense population of dispersed sperm, other spermatogenic cells and histiocytes (H and E, ×500); (c) Tuberculous epididymo-orchitis. Smear shows clusters of epithelioid cells and lymphocytes in a background of neutrophils (H and E, ×500); (d) Elephantiasis. Smear shows single intact microfilaria against a background of inflammatory cells and cellular debris (Pap, ×500)

Of the 17 cases of chronic epididymitis, tubercular etiology was ascertained in 14 cases with smear showing either epithelioid granulomas or caseous necrosis or both, in an inflammatory background [Figure 1c]. Of the remaining three cases, two were classified as chronic nonspecific epididymitis as only mixed inflammatory infiltrate was seen and one aspirate was inadequate for diagnosis.

Aspiration from the case of clinical elephantiasis yielded milky fluid, which on light microcopy showed two intact microfilariae along with histiocytes, other inflammatory cells and cellular debris [Figure 1d].

Of the swelling in the scrotal wall, FNAC of the three multinodular eruptive swellings diagnosed to be calcified masses by USG showed calcific material with very scant cellularity composed of necrotic and degenerating cells. A swelling suspected radiologically to be scrotal neoplasm yielded a scanty aspirate. Thus, FNAC did not add any further information to the radiological impression of the lesions of the scrotal wall.

Histological follow-up was available in 47 (72.3%) of the cases, of which cytological correlation was seen in 44 cases. It was helpful for the definitive diagnosis in 7 cases (10.8%) – one case of tubercular epididymitis turned out to be nonspecific epididymitis. One patient diagnosed as spermatocele on cytology was found to be a case of post-vasectomy syndrome [Figure 2]. It was also helpful for the definitive diagnosis of a case of inflammatory pseudotumor [Figure 3a and b], which was diagnosed as paratesticular neoplasm radiologically and as nonspecific epididymitis cytologically. Three cases showing calcified scrotal mass were diagnosed as scrotal calcinosis [Figure 4a, and c] and one case of scrotal neoplasm was found to be scrotal metastasis from a testicular neoplasm.

Figure 2.

Late post-vasectomy syndrome. Smear shows sperm granuloma around a tubule showing two multinucleated giant cells, epithelioid cells, inflammatory cells and histiocytes (H and E, ×250)

Figure 3.

(a) Fibrous pseudotumor (gross). Cut section of tumor is pale homogenous and attached to capsule of testis; (b) Fibrous pseudotumor – Section shows fascicles of spindle-shaped cells with few inflammatory cells (H and E, ×250)

Figure 4.

(a) Scrotal calcinosis – Multinodular, large, yellowish swellings on scrotum; (b) Scrotal calcinosis – Smear shows calcium deposits and few degenerating cells (H and E, ×500); (c) Scrotal calcinosis – Section shows intradermal basophilic calcific masses, with overlying epidermis (H and E, ×50)

Discussion

Studies dealing with intrascrotal pathology, especially those attempting to find a correlation between clinical, radiological and pathological data, are few and far between. Most of the studies have evaluated the role of cytology in male sterility or testicular lesions. There are only few studies based on the role of cytology in epididymal nodule.[3,4]

In the present study, extra testicular pathology was found in 65 cases (72.2%) of the total scrotal lesions, as compared to 80% found in study by Rholl et al.[5]

Commonest site to be involved was the epididymis [40 cases (61.5%)], comparable to the finding by Rholl et al.[5] This was followed by the tunica vaginalis; [17 cases (26.1%)], the spermatic cord and scrotal wall [2 cases (6.2%) each].

The most common category of lesions was cystic lesion [32 cases (49.3%)], with hydrocele being the most frequent. This was followed by inflammatory lesions [28 cases (43.1%)] and tumor and tumor-like lesions [5 cases (7.6%)], similar to the finding by Perez-Guillero et al.[6] who, in their study of 89 palpable lesions of the scrotum, testicle and epididymis, found cystic lesions (48.3%) and inflammatory pathology (25.8%) to be the most frequent findings.

However, in a study by Handa et al.[7] on 137 cases of non-neoplastic testicular and scrotal lesions, inflammatory lesions were found to be the commonest [52 cases (31.7%)], followed by non-inflammatory lesions [42 cases (25.6%)] and infertility [43 cases (26.2%)].

Chronic inflammatory lesions (26.2%) were found to be much common than acute inflammatory lesions (15.4%), as opposed to the study results of Gerscovitch[8] where chronic inflammatory lesions were less common. Tuberculosis was the most frequent etiology of chronic epididymitis, followed by chronic non-specific epididymitis, and these findings were similar to those of Woodward et al.[9] and Viswaroop et al.[10]

Scrotal swelling being the criterion for inclusion was found in 100% cases, followed by scrotal pain and tenderness in 56.9% of the cases.

Acute scrotum, one of the main symptoms of the patients presenting with scrotal pathology, was found in only 11 (16.9%) of our cases, the reason being the most important cause of acute scrotum, i.e., torsion of testis,[11] was excluded from our study. Earlier studies have shown that the most frequent cause of acute scrotum in adult is inflammatory disease, being responsible for 75% of the cases,[12] though higher figure (90.9%) was found in the present study probably because of complete exclusion of cases of torsion, which, though rare, is found in adults. According to Lyronis et al.,[13] the commonest cause of acute scrotum in children was epididymo-orchitis, followed by torsion of appendages. In contrast, the most common cause in boys of preschool age was spermatic cord torsion.

Clinically, chronic epididymitis poses a diagnostic problem, as fever and pain are often absent and patient usually presents with firm paratesticular mass.[9] Sonographically, the enlarged and hyperechoic epididymis found in epididymitis is indistinguishable from a tumor of the epididymis.[14] However, in our study, the paratesticular location with separate visualization of the epididymis as well as calcification led to a suspicion of neoplasm radiologically. However, in both these entities, pathological study was found to play an important role. Cytological examination of the lesion confirmed the chronic inflammatory nature of the swelling and its categorization into tubercular and chronic nonspecific type. Histopathological examination confirmed all the cases diagnosed as tubercular on cytology and labeled another case suspected as chronic epididymitis as tubercular.

Cystic masses of epididymis constituted 18.5% (12 cases) in our study, with true epididymal cysts being more common. However, in post-vasectomy patients, spermatoceles were common, which is similar to the report of Holden and List.[15]

Diagnostic confusion in cases of hydrocele did not arise since in all the cases a fluctuant swelling was palpable separate from the testis. The two entities – epididymal cyst and spermatoceles – were, however, clinically and radiologically indistinguishable and their cytology contributed in differentiating the two, as the aspirated fluid in these entities was different both macroscopically as well as microscopically. But the clinical impact was not much as both conditions had to be excised if large.

According to many studies, hydrocele and more complex fluid collections are easily identified by ultrasonography. However, it is not possible to differentiate hematocele from exudative hydrocele by ultrasound alone, and therefore any fluid collection that entirely encircles the testis should be explored and drained.[16] So, in the present study, after categorization of fluid collection into simple and complex hydrocele using ultrasonography, aspiration was done. This led to further categorization of complex hydroceles into hematoceles and pyocele.

The only true neoplasm detected in the present study was metastasis to the scrotal wall from an ipsilateral testis having embryonal carcinoma. An inflammatory pseudotumor of the tunica was the only benign lesion which mimicked a neoplasm. Each of these accounted for 1.5% of the extratesticular lesions.

A study by Upton and Das[17] on solid intrascrotal masses, both testicular and paratesticular, showed a higher incidence of benign neoplasm in the paratesticular structures, with adenomatoid tumor being the commonest and fibrous pseudotumor being the second most common benign tumor of testicular adnexa. A study of solid extratesticular masses that underwent surgical resection by Beccia et al.[18] showed an overall malignancy rate of 3%, in which the commonest lesion was lipoma. Another study of 19 patients with extratesticular masses using ultrasonography by Frates et al.[1] gave a higher malignancy rate of 16%, the commonest lesion being adenomatoid tumor. However, the number of patients with neoplasms is too small in the present study to be compared with any of the above.

Conclusion

Scrotal diseases, though previously considered to be a forte of clinician, cannot be specifically diagnosed without the help of ancillary techniques. The present study also showed that ultrasound, though reliable in distinguishing between intratesticular and extratesticular lesions and to characterize them as cystic and solid, cannot distinguish benign from malignant pathology. The advantage of FNAC is that apart from being simple, safe, and cost-effective, it also helps to classify cystic masses of tunica vaginalis and of the epididymis on the basis of the contents and defines the etiology of the chronic inflammatory lesions. In corroboration with clinico-radiological diagnosis, FNAC also helps to pinpoint a specific diagnosis, thereby influencing the clinical management. It may at times have therapeutic implication, e.g., in cases of hydroceles, which may either be completely drained or sclerosants injected. Definitive diagnosis, however, in many lesions is still possible only on histopathology.