A case of granular cell tumor

A case presentation presented on December 2013 Egyptian society of Pathology meeting.

1. CASE PRESENTATION BY Salma Tarek Mahmoud Assistant Fellow at Ahmed Maher Teaching Hospital

2. A 22 ys old female patient complaining of left breast mass. Excision was done

3. Gross examination A fairly defined rubbery mass measured 10x7x7 mm. Cut section was homogenous grayish white

4. Microscopic examination

5. PAS staining was done

6. Cytokeratin

7. c

8. Diagnosis Granular cell tumor

9. Granular cell tumor( GCTs) Uncommon tumor thought to be derived from schwann cells. Abrikossoff first described this tumour in 1926 as ‘‘granular cell myoblastoma ’’, assuming it was of myogenic origin; some even refer to the lesion as ‘‘ Abrikossoffoma ’’. Considered benign, only rare reports of malignant variants Incidence Occur in any age but are most common in fourth, fifth and sixth decades of life, rare in children. It is about twice as common in women as in men.

10. Site Arise in any organ as solitary painless nodule Most frequently in oral cavity typically the tongue Internal organs, particularly larynx, bronchus, stomach and bile duct. Clinically Approximately 10–15% of patients have lesions at multiple sites. Multiple lesions may appear synchronously or over a period of many years. Gross picture Poorly circumscribed nodule less than 3 cm Cut section pale yellow-tan or gray.

11. Microscopically Infiltrating compact nests or sheets Bland looking large polygonal to spindle cells Eosinophilic cytoplasmic granules Nuclei are small dark monotypic +/- vacoulization and clearing

12. Pseudoepitheliomatous hyperplasia of the overlying squamous epithelium, should not be mistaken for squamous cell carcinoma. In close proximity to peripheral nerve bundles

13. Special Stains and Immunohistochemistry S-100 protein: highlights cytoplasmic granularity with strong cytoplasmic and nuclear staining Carcinoembryonic antigen (CEA): diffuse immunoreactivity Cytokeratin and (EMA) are negative Myoglobin negative (ER) and (PR) are negative PAS positive diastease resistant cytoplasmic granules

14. GCTs in breast I ncidence 5%- 6% in breast. Premenopausal women in 40’s, reported in adolescents, elderly women and men May be more common in African-American women Site Superior medial quadrant (course of supra- clavicular nerve) Clinical features Usually solitary unilateral, rarely multiple Painless firm mass, may be associated with skin retraction and nipple inversion

15. Gross Cut surface is fairly defined white - gray to yellow Less than 3 cm but reported up to 9 cm.

16. Radiologically X-ray Mammography Suggestive of malignancy due to apparent infiltration, stellate mass without calcification

17. Differential Diagnosis

18. D.D Reactive histocytic lesion Invasive breast carcinoma Apocrine carcinoma Myoblastomatoid , Lobular carcinoma histocytic variant Alveolar soft part sarcoma Metastatic malignant melanoma Metastatic renal cell carcinoma

19. Reactive Histocytic lesions Dispersed histocytes with mixed population of inflammatory cells

20. Older age Usually in outer quadrant large cells with pleomorphic nuclei, prominent nucleoli, mitosis Typically associated with intra- ductal component IHC : Positive for cytokeratin , GCDFP-15 Apocrine carcinoma

21. Myoblastomatoid invasive lobular carcinoma, histocytic variant Older age Associated with infiltrative component Loosely cohesive tumor cells IHC: Positive for cytokeratin

22. Alveolar soft part sarcoma Deep soft tissue Pleomorphic cells Cells are divided into packets by thin walled vessels Alveolar pattern if cells discohesive Vascular invasion common IHC : Positive for Myoglobin

23. Metastatic malignant melanoma Old age History of primary elsewhere Nuclei usually show nucleoli Cytoplasmic pseudo-inclusions Melanin pigments IHC : Positive HMB- 45

24. Metastatic renal cell tumor History of primary elsewhere Nests, separeted by sinasoids Well defined cell membrane Nuclear pleomorphism Prominent nucleoli in high grades Clearing of cytoplasm IHC: positive for EMA

25. Take home message GCTs is an uncommon tumor occur in any age. 5%-6% incidence in breast, inner upper quadrant. Pose a real diagnostic challenge for physicians. Clinically and radiologically misdiagnosed as carcinoma Preoperative diagnosis with core needle biopsy is important because treatment is with wide excision , rather than mastectomy. Less than 1% of all GCTs, including mammary lesions, are malignant. The prognosis for benign GCT of the breast is excellent. Recurrence occurs in 2-8% of individuals after excision with wide margins