CT scan of the neck (axial cuts)

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口腔病理科 On-Line KMU Student Bulletin

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原文題目(出處): Hyalinizing clear cell carcinoma of the base of tongue 原文作者姓名: K Pujary, S Rangarajan, D R Nayak, R Balakrishnan, V

Ramakrishnan

通訊作者學校: Department of Pathology, Kasturba Medical College &

Hospital, Manipal, India 報告者姓名(組別): 魏大鈞(intern B)

報告日期: 97.01.08

內文:

Abstract

z Hyalinizing clear cell carcinoma is a rare, low-grade neoplasm of the minor salivary glands

z Composed exclusively of epithelial cells with optically clear cytoplasm z Only a few isolated cases reported involve the base of tongue

z Tx Î wide excision and selective neck dissection, with or without radiotherapy z More commonly in adult females

z Positive for cytokeratin and negative for S-100 and smooth muscle actin (SMA) z Originates from epithelial cells and not myoepithelial cells

Case report

z A 57-year-old male felt foreign body sensation in the throat for 1 month z Smoking (-), Alcohol drinking(-)

z By indirect laryngoscopy, a 3 cm*3 cm smooth submucosal mass towards the left side of the base of tongue, extending to the tonsillolingual sulcus and vallecula

z Palpation/firm, tender(-), bleeding(-), no palpable cervical lymphadenopathy, tongue movement was normal

CT scan of the neck (axial cuts)

z Heterogeneously enhancing mass at the base of tongue towards the left z Involve the ipsilateral mylohyoid m. and bilateral genioglossus m.

z Extend to the left vallecula and abutting the epiglottis, displacing it posteriorly

Operation procedure

z Excision of the mass via a transcervical approach under general anaesthesia

z Retract and cut the myohyoid m. attached to superior of hyoid bone to expose the tumor z The tumor was removed in toto by blunt dissection and a supraomohyoid neck

dissection was done

Grossly

z It was solid and grey white on cut surface measuring about 3cm*2cm*1.5cm

Microscopically

z Partly encapsulated with infiltrative margins, and was composed of large polygonal cells with clear cytoplasm and distinct cell borders (Fig. a).

L Dorsal

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z In some areas, these cells were admixed with smaller cells having amphophilic cytoplasm

z The nuclei Î large, oval to slightly irregular with coarse chromatin

z The neoplastic cells Î arranged in nests and trabeculae, surrounded by fibrous stroma showing hyalinization (Fig. a)

z Periodic acid–Schiff (PAS) stain with and without diastase showed intracytoplasmic glycogen in some of the tumor cells (Fig. b)

z Intracytoplasmic mucin or fat : (-) z Atypical mitosis or necrosis : (-)

z Immunohistochemistry Î the tumour cells were positive for cytokeratin (AE1/AE3;

Dako) (Fig. c).

z S-100 (Dako) and vimentin (Dako) : (-)

z According to the light microscopic and immunohistochemical features Î hyalinizing clear cell carcinoma

Post-op

z 3 weeks after surgery, the patient received postoperative radiotherapy of 60Gy in 30 fractions over 6 weeks

z Follow up after 18 months there was no evidence of recurrence or distant metastasis

Discussion

z Hyalinizing clear cell carcinoma (HCCC) is a distinct clinico-pathological entity

Microscopically

Î Composed exclusively of monomorphic undifferentiated cells with optically clear cytoplasm

Clinically

Î Less than 1% of all salivary gland tumour

Î Arise from the minor salivary glands within the oral cavity Î commonly located in the palate, lips and buccal mucosa

Î Base of tongue, hypopharynx, larynx, nasal cavity and jaw bones are rare Î More common in women between the fifth and seventh decades Î A slow growing and painless submucosal mass

Î a low propensity towards recurrence nodal and distant metastasis Î clear cell carcinoma, glycogen-rich clear cell adenocarcinoma and

glycogen-rich clear cell carcinoma

z Histologically

Î The tumour has infiltrative borders, with the neoplastic clear cells arranged in thick trabeculae, nests, cords or solid sheets with a hyalinizing stroma Î Eosinophilic cells, as seen in the present case, may also be a component of the

tumor

Î Distinct cell borders with uniform small nuclei

Î PAS-positive diastase-sensitive material, representing glycogen, in the cytoplasm Î Immunohistochemistry shows expression of epithelial markers especially

cytokeratins

Î negativity for vimentin, S-100 and SMA Î don’t contain mucin

z Histopathology differential diagnosis : mucoepidermoid carcinoma, acinic cell

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carcinoma, clear cell oncocytoma, epithelial myoepithelial carcinoma, malignant myoepithelioma, sebaceous carcinoma, odontogenic tumours , metastatic renal cell carcinoma

z Clinical differential diagnosis of the lesion at the base of tongue : epithelial

malignancies, granulomatous conditions, lingual thyroid, prominent lingual tonsils and cysts

z As these tumors are rare, there is no standard treatment protocol

In conclusion

z HCCC is a rare minor salivary gland tumor exhibiting the behavior of a low-grade malignancy

z It has a better prognosis than the other salivary gland tumors showing clear cells z Wide local excision achieves adequate locoregional control of small primary tumors

題號 題目

1 It is composed of a mixture of mucus-producing cells and squamous (epidermoid) cells. In some tumor also show variable numbers of clear cell. Which one is the proper diagnosis ?

(A) Hyalinizing clear cell carcinoma (B) epithelial myoepithelial carcinoma (C) mucoepidermoid carcinoma (D) clear cell oncocytoma

答案(C) 出處:oral & maxillofacial pathology p420

題號 題目

2 All of the following salivary gland disease can find clear cells except for

?

(A) Oncocytoma

(B) Acinic cell adenocarcinoma (C) mucoepidermoid carcinoma (D) Warthin tumor

答案(D ) 出處:oral & maxillofacial pathology p414、p420、p423

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