Présentation Clinique

F de 35 ans, se plaignant d'une tumfaction ferme de la parotide droite, augmentant de volume progressivement depuis 3 ans, sans douleur ou déficit facial.

Pathologie:

Macroscopie

La parotide mesurant 4,5 x 2,7 x 1,3 cm comporte une zone tumorale mal délimite de 1,5cm de consistance ferme, blanchtre, homogéne.

Microscopie

Les prélévements réalisés présentent des remaniements inflammatoires chroniques au niveau du tissu glandulaire, avec métaplasie canalaire. Dans la zone tumorale, des lobules et les canaux sont entourés voire engainés par des nappes cellulaires avec un stroma fibreux.

La prolifération infiltrant le tissu péri-capsulaire, s'étend dans les septa inter-lobulaires. Elle est formée de nappes de cellules de grande taille à cytoplasme abondant, granulaire, noyaux ovoïdes ou arrondis avec légère anisonuclose. Des globules ou vésicules éosinophiles intracytoplasmiques, PAS positives sont perçues. Elles montrent une richesse cytoplasmique en enzymes hydrolytiques (Luxol).

L'immunohistochimie montre une positivitéà la proteine S100, et la Vimentine dans ces cellules, objectivant leur extension peri-canalaire dans certains foyers.

Diagnostic Proposé: 

Tumeur à cellules granuleuses

Abstracts et Réferences

Ear Nose Throat J 2001 Jul;80(7):454-7 Granular cell tumor of the parotid: a case report and literature review. Smith JL 2nd, Feehery JM, O'Hara BJ, Rao VM, Vernose GV. Jefferson Medical College, Philadelphia, USA. Granular cell tumors are relatively uncommon soft tissue lesions that originate in Schwann's cells. Although these tumors can occur at any site, their presence in the parotid gland is very unusual. This article describes one such case in a 48-year-old woman, followed by a brief review of the literature on this subject.  Ann Diagn Pathol 1999 Feb;3(1):35-8

Granular cell tumor of the parotid.

Said-Al-Naief N, Ivanov K, Jones M, Som P, Urken M, Brandwein M.

Departments of Otolaryngology and Pathology, Mount Sinai School of Medicine, New York, NY, 10021, USA.

A case of granular cell tumor of the major salivary glands is presented. This tumor appeared as an expansive multinodular mass that arose from facial nerve trunks. The presenting symptoms of facial pain and paresis and the intraoperative findings of tumor adhesion to nerves led to the clinical impression of malignancy. At intraoperative consultation, the tumor resembled an acinic cell carcinoma. Pathologists should be aware that granular cell tumors may involve the major salivary glands and that it should be considered in the diagnostic differential diagnosis

Int J Oral Maxillofac Surg 1999 Oct;28(5):383-4

Granular cell tumor of the parotid gland. A case report.

Carinci F, Marzola A, Hassanipour A.

Department of Maxillofacial Surgery, University of Ferrara, Italy.

Granular cell tumor (GCT), or granular cell myoblastoma, is a relatively uncommon lesion of the soft tissues. The tumor is thought to derive from a Schwann cell or from a perineural undifferentiated mesenchymal cell. GCT can occur in any organ, but the parotid gland is very unusual. A case of GCT of the parotid gland in a 30-year-old woman is described.

J Am Acad Dermatol 1981 Aug;5(2):171-82

Granular cell tumor. An analysis of 16 cases and review of the literature.

Apisarnthanarax P.

Sixteen patients with granular cell tumors were seen between 1964 and 1979. The medical data of these patients showed an average age incidence of 39 years and a greater frequency among Negroes (69%) and in female patients (62.5%). The most common sign (in 12 of 16 patients) was the presence of an asymptomatic mass. There was a total of 88 tumors in 16 patients; 74 arose in the skin, 6 in the oral cavity, 2 each in the breast and perineum, and 1 each in the larynx, parotid gland, eyelid, and appendix. Multiple tumors were noted in 4 patients (25%), all of whom were Negroes. The histogenesis of this tumor is still controversial but appears to favor the theory of multipotential undifferentiated mesenchymal cell origin.

Laryngoscope 1980 Oct;90(10 Pt 1):1646-51

Multiple granular cell tumor.

Jones JK, Kuo TT, Griffiths CM, Itharat S.

Eleven cases of granular cell tumor were reviewed. In two of the cases multiple sites of involvement were seen. The tumor occurred in the oral cavity in both of these cases and each was initially wrongly diagnosed as squamous cell carcinoma. The most common site was the subcutaneous tissue (nine patients) and the tongue was involved in three cases. In one patient the parotid gland was involved. Eight of the patients were females and three were males; seven were black and four were white. The importance of differentiating between squamous cell carcinoma and granular cell tumor is stressed, as is the need for a simple wide surgical excision.

Granular cell tumor (Ackerman's Surgical Pathology, 8th Ed.)

The classic location of granular cell tumor, also known as granular cell myoblastoma, is the tongue. It has been seen, however, in many other locations such as the skin, vulva, breast, larynx, bronchus, esophagus, stomach, appendix, rectum, anus, bile ducts, pancreas, urinary bladder, uterus, brain, pituitary gland, and soft tissue. Multiplicity of lesions can be observed, particularly in black patients. A few congenital examples have been reported, most of them located in the gingiva, but some exhibiting systemic involvement.
These tumors are usually small, although we have seen cases measuring up to 5 cm in diameter. They have a hard consistency and ill-defined margins. This, plus the ulceration sometimes complicating the larger cutaneous tumors, explains why they are sometimes confused clinically and on gross inspection with a malignant neoplasm. Rarely, they have a polypoid shape. The individual cells are large and their cytoplasm highly granular . Most granules are small and regular. They alternate with larger round droplets having a homogeneous eosinophilic appearance and a stronger PAS positivity. If the tumor grows near an epithelial surface, such as the skin, vulva, or larynx, secondary epithelial hyperplasia occurs that may be incorrectly diagnosed as carcinoma. Elastosis is often present in the stroma.

Histochemically, the cytoplasmic granules contain large amounts of hydrolytic enzymes (such as acid
phosphatase), and they are consistently positive for Luxol fast blue. Ultrastructurally, they have the
appearance of lysosomes. Other interesting electron microscopic findings are the presence of a second cell population with "angulated bodies" resulting in a Gaucher celllike appearance and of replicated basal lamina material around the granular cells, the latter suggesting repeated cycles of cellular injury and repair.
Immunohistochemically, positivity has been described (in at least some of the lesions) for S-100 protein, laminin, HLADR, myelin basic protein, and CEA. The presence of the latter two markers remains controversial; the apparent CEA reactivity may be caused by the presence of a cross-reacting antigen. The expression of HLADR is thought to be related not to the cell of origin but
rather to some common immunologic pathogenesis.

The large majority of the granular cell tumors pursue a benign clinical course. Most cases reported in the old literature as malignant granular cell myoblastomas are in reality examples of alveolar soft part sarcoma. However, there have been several well-documented cases of tumors with a light and electron microscopic appearance comparable with that of granular cell tumor that have resulted in distant metastases.

The histogenesis of this lesion is still discussed. Most writers on the subject favor a Schwann's cell origin, based on histochemical, immunohistochemical, and ultrastructural findings and on the occurrence of typical lesions, within nerves. However, in some lesions, there is no evidence of Schwann's cell participation. Furthermore, changes histochemically and ultrastructurally indistinguishable from those previously discussed have been documented in neoplastic and non-neoplastic smooth muscle cells and in tumoral ameloblasts. We therefore favor the view that granular cell tumor is not a specific entity but rather the expression of a degenerative change that can occur not only in Schwann's cells but also in a variety of other cell types, whether previously normal or forming part of a benign or a malignant neoplasm, such as MPNST, leiomyosarcoma, or angiosarcoma. We favor making the diagnosis of granular cell tumor only when the entire lesion is granular and to designate the other cases according to their basic component, noting that focal granular changes are present.