Encyclopedia of Pathology

Living Edition
| Editors: J.H.J.M. van Krieken

Granular Cell Tumor, Genitourinary Tract

  • Cecilia Taverna
  • Alessandro FranchiEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-319-28845-1_5007-1

Synonyms

Definition

Granular cell tumor (GCT) is a benign neuroectodermal tumor composed by large polygonal cells with abundant granular cytoplasm (Gurzu et al. 2015). The lesion is usually benign, even though rare malignant cases are reported (Richmond et al. 2016; Fanburg-Smith et al. 1998).

Clinical Features

  • Incidence

    Granular cell tumor is quite rare in the male genitourinary tract. Indeed, 17 cases are reported in the bladder and < 20 cases in male genitalia (Bedir et al. 2017; Pu et al. 2015).

  • Age

    The lesion can occur at all ages (bladder 14–70 years, external male genitalia 6–89) (Cheville and Folpe 2016; Richmond et al. 2016; Pu et al. 2015).

  • Sex

    In the bladder, it occurs in both males and females, while in the external genitalia occurs only in males (Cheville and Folpe 2016; Bedir et al. 2017; Pu et al. 2015; Richmond et al. 2016).

  • Site

    The tumor can occur in the bladder, urethra, external genital tract (penis and scrotum), and occasionally in the prostate (Cheville and Folpe 2016; Bedir et al. 2017; Pu et al. 2015; Richmond et al. 2016).

  • Treatment

    Conservative surgical excision with clear surgical margins is the treatment of choice, with a very low risk of recurrences (2–8%) (Bedir et al. 2017; Gurzu et al. 2015).

  • Outcome

    The lesion is benign, even if rare malignant cases are reported (Cheville and Folpe 2016; Richmond et al. 2016).

Macroscopy

The lesion is usually small (0.6–2.5 cm), but sometimes it can be larger, especially in the bladder (Cheville and Folpe 2016). On gross examination, the lesion is soft, with ill-defined borders and yellow or white-cream color (Bedir et al. 2017; Pu et al. 2015).

Microscopy

At low power, GCT is composed of cohesive groups of large cells arranged in lobules separated by fibrous septa. At higher magnification, cells display polygonal shape, with small, uniform-sized round nuclei with small nucleolus, abundant granular cytoplasm with occasional larger droplets and well-defined cytoplasmic borders (Fig. 1). Mitotic activity is usually low (1%). Malignant cases show necrosis, spindling, vesicular nuclei with large nucleoli, increased mitotic activity (>2 mitoses/10 high-power fields at 200× magnification), high nuclear to cytoplasmic (N:C) ratio, and pleomorphism (Cheville and Folpe 2016; Bedir et al. 2017; Pu et al. 2015; Richmond et al. 2016; Gurzu et al. 2015; Fanburg-Smith et al. 1998).
Fig. 1

Neoplastic cells present small, uniform-sized round nuclei, abundant eosinophilic granular cytoplasm, and well-defined cytoplasmic borders

Immunophenotype

The lesion is typically positive for protein S100, NSE, EMA, CD56, and inhibin in most of the cases, while positivity of other markers, such as vimentin, synaptofisin, calretinin, and laminin, is very variable (Gurzu et al. 2015). In the atypical cases, loss of inhibin and CD56 and gain of c-KIT and RET kinase expression are found (Gurzu et al. 2015). Cytokeratins, vascular markers, desmin, SMA, calretinin, maspin, and GFAP are usually negative (Bedir et al. 2017; Pu et al. 2015; Gurzu et al. 2015).

Differential Diagnosis

The differential diagnosis includes other lesions that display granular cytoplasm. Other lesions that have to be differentiated from GCT are malakoplakia, carcinomas, leiomyoma, leiomyosarcoma, dermatofibroma, dermatofibrosarcoma protuberans, malignant schwannoma (MPNST), angiosarcoma, and melanoma (Bedir et al. 2017; Gurzu et al. 2015; Fanburg-Smith et al. 1998).

The malignant counterpart of this entity differs from GCT for many features, including the presence of necrosis, pleomorphism, high mitotic activity, spindle-shaped tumor cells, vesicular nuclei with large nucleoli, and high nuclear to cytoplasmic ratio (Bedir et al. 2017; Gurzu et al. 2015). One study established that if the lesion shows three or more criteria of malignancy, it is classified as histologically malignant, while those that meet one or two criteria are classified as atypical (Fanburg-Smith et al. 1998).

Immunohistochemistry is very useful to distinguish this lesion from carcinomas, as well as from melanoma and sarcomas. A difficult differential diagnosis is between malignant GCT and MPNST. Important features that may differentiate GCT from MPNST are the absence of origin from nerve and diffuse S100 positivity of GCT (Fanburg-Smith et al. 1998).

References and Further Reading

  1. Bedir, R., Yılmaz, R., Özdemir, O., & Uzun, H. (2017). Granular cell tumor of the urinary bladder. Turkish Journal of Urology, 43(3), 383–385.CrossRefGoogle Scholar
  2. Cheville, J., & Folpe, A. (2016). Tumours of the genitourinary tract in WHO classification of tumours of the urinary system and male genital organs (4th edn, pp. 122–127). IARC, Lyon.Google Scholar
  3. Fanburg-Smith, J. C., Meis-Kindblom, J. M., Fante, R., & Kindblom, L. G. (1998). Malignant granular cell tumor of soft tissue: Diagnostic criteria and clinicopathologic correlation. The American Journal of Surgical Pathology, 22(7), 779–794.CrossRefGoogle Scholar
  4. Gurzu, S., Ciortea, D., Tamasi, A., Golea, M., Bodi, A., Sahlean, D. I., Kovecsi, A., & Jung, I. (2015). The immunohistochemical profile of granular cell (Abrikossoff) tumor suggests an endomesenchymal origin. Archives of Dermatological Research, 307(2), 151–157.CrossRefGoogle Scholar
  5. Pu, C. X., Gao, L., Bai, Y. J., & Han, P. (2015). Granular cell tumor of the urethra: A case report and literature review. Asian Journal of Andrology, 18(6), 946–948.PubMedCentralGoogle Scholar
  6. Richmond, A. M., La Rosa, F. G., & Said, S. (2016). Granular cell tumor presenting in the scrotum of a pediatric patient: A case report and review of the literature. Journal of Medical Case Reports, 10(1), 161.CrossRefGoogle Scholar

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© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Department of Health SciencesUniversity of FlorenceFlorenceItaly
  2. 2.Department of Translational Research and of New Technologies in Medicine and SurgeryUniversity of PisaPisaItaly