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Granular cell tumor of the scrotum

  • Author(s): Craig, E;
  • Rodriguez, R;
  • Ruben, B
  • et al.
Main Content

Granular cell tumor of the scrotum
E Craig1, R Rodriguez2, B Ruben3
Dermatology Online Journal 11 (2): 25

1. Department of Dermatology, UC Davis Medical Center, Sacramento, CA, USA2. Department of Pathology, UC Davis Medical Center, Sacramento, CA, USA 3. Departments of Dermatology and Pathology, UC San Francisco, CA, USA


Introduction

Granular-cell tumor is an uncommon soft tissue neoplasm with predilection for the head and neck region, especially the tongue. Women are more commonly affected than men, and blacks more than whites. The most common presentation is that of a less than 2-cm smooth asymptomatic skin-colored nodule. It is thought to be of neural origin, although granular cell change has been reported in a wide variety of neoplastic lesions, including smooth muscle tumors [1, 2]. Rare malignant granular-cell tumors have been reported [3]. The characteristic histopathology of a granular-cell tumor is a nonencapsulated group of polygonal cells with coarse granular eosinophilic cytoplasm, thought to consist of lysosomes. Malignant granular-cell tumors are rare, but features suggesting that diagnosis include large size, necrosis, high mitotic activity, tumor cell spindling, and vesicular nuclei with large nucleoli [4]. We report a granular-cell tumor of unusual location, the scrotum.


Clinical synopsis


Figure 1 Figure 2

A 67 year-old African American male presented to the clinic with an approximately 2-year history of an asymptomatic nodule on the left side of his scrotum (Fig. 1). He stated that the lesion had been slowly increasing in size. Examination revealed an approximately 2-cm soft rubbery mobile nodule (Fig. 2). A working diagnosis of cyst vs. scrotal calcification was made and a biopsy of the lesion was performed.


Figure 3 Figure 4
Figure 3 H&E (12.5X)
Figure 4 H&E (100X)

Figure 5 Figure 6
Figure 5 H&E (400X)
Figure 6 S100 (200X)

Figure 7
Figure 7 Smooth muscle actin (100X)

Biopsy revealed a poorly circumscribed proliferation of large polygonal cells with abundant granular cytoplasm, set among collagen bundles. There was no significant epidermal hyperplasia. The patient returned for definitive surgical removal approximately 6 weeks later.

The excisional specimen was an elliptical segment of dark-tan skin measuring 3.5 x 1.9 x 1.1 cm. Sectioning revealed a firm, light-tan, well-circumscribed and nonencapsulated solid mass measuring 1.6 x 1.4 cm. Microscopically, the tumor was composed of large polygonal cells with basophilic nuclei and granular cytoplasm (Figs. 3-5). There was minimal pleomorphism and mitoses were not evident. The eosinophilic granules were small and irregular. Immunohistochemistry was positive for S100 and negative for smooth muscle actin (Figs. 6 and 7, respectively).


Comment

To the best of our knowledge, only four other cases of scrotal granular-cell tumors have been reported [5, 6, 7, 8]. Given the presence of scrotal smooth muscle (Dartos), we postulated that this tumor might in fact represent a granular cell leiomyoma. The granular cells, however, do not stain with smooth muscle actin antisera (Fig. 7), whereas the underlying scrotal smooth muscle clearly does. This suggests that this neoplasm is not of muscle origin. Because it is clearly S100 positive (Fig. 6), this likely represents a granular cell Schwannoma of the scrotum. The paucity of similar cases in the literature suggests that the scrotum is a unusual location for such a tumor, however an alternative explanation is that scrotal granular-cell tumors are rarely biopsied.

References

1. Mentzel T, et al. Granular Cell Change in Smooth Muscle Tumours of Skin and Soft Tissue. Histopathology, 1994, 24, p. 223-31.

2. Ordonez, NG. Granular Cell Tumor: A Review and Update. Adv Anat Pathol. 1999. Jul 6[4], p.186-203.

3. Berg, JC, et al. Unusual Presentation of a Malignant Granular Cell Tumor of the Pelvis: Case Report and Literature Review. Gynecologic Oncology 90 (2003) p.224-30.

4. Fanburg-Smith JC, et al. Malignant Granular Cell Tumor of Soft Tissue: Diagnostic Criteria and Clinicopathologic Correlation. Am J Surg Path, 22[7], Jul 1998, 779-194.

5. Altman C., et al. Multiple cutaneous granular cell tumors of the scrotum. Cutis, 63[2], Feb 1999, 77-80.

6. Bryant, J. Granular cell tumor of penis and scrotum. Urology, 45[2], Feb 1995, 332-4.

7. Menendez, LV, et al. Unusual Location of a Granulosa Tumor. Arch Esp Urol, 2001, May 54[4], p374-5.

8. Medina PM, et al. Granular Cell Tumor of the Scrotum with High Pseudoepitheiomatous Hyperplasia. Arch Esp Urol, 1999, Mar 52[2], p.169-70.

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