Acantholytic squamous cell carcinoma of soft palate-case report and literature review.

Acantholytic squamous cell carcinoma (ASCC) is one kind of squamous cell carcinoma subtype malignant tumor. It was first described by Lever in 1947 as adenoacanthoma of the sweat glands. With subsequent studies, it became evident that these tumors are distinct variants of squamous cell carcinoma and not eccrine in origin. More rarely, it has been documented in the oral mucosal membranes.1, 2, 3 A review of the English literature revealed 13 cases in the oral mucosa membranes. The case described herein was the 14th case reported in the oral cavity and the only case which affected the soft palate.

A 55-year-old man visited our oral-maxillofacial surgery department in August 2007. Clinical examination revealed a reddish ulcerative lesion over the left soft palate of about 2 cm × 2 cm in size. An incisional biopsy was performed and histopathologic examination revealed ASCC (Figure 1a,b). Computed tomography demonstrated a soft tissue tumor involving the left soft palate, maxillary sinus and pterygoid plate, and enlarged lymph nodes in the left submandibular area. A chest film and abdominal echo showed no sign of distant metastasis and whole body bone scans demonstrated bony destruction in the left sphenoid bone. The patient received surgical treatment. The procedure included left side modified radical neck dissection, wide excision of the tumor, and hemimaxillectomy. Then, the defect was reconstructed by anterolateral thigh free flap (Figure 1d) The patient received post-operative adjuvant radiation therapy by using the intensity-modulated radiation therapy (IMRT). The patient was treated with an IMRT gave a total of 6600 cGy and six time chemotherapy. The patient remained well, with no evidence of tumor recurrence or distant metastasis for >5 years follow up (Table 1, Table 2).

Figure 1

Histopathologic picture of our case of acantholytic squamous cell carcinoma. Infiltrating tumor cell nests with the characteristic pseudoglandular pattern, with evidence of acantholysis is present in most of the tumor cell nests: (A) hematoxylin and eosin, 40×. A higher magnification shows pseudoglandular structure lined by dysplastic squamous cells with the acantholytic cells and keratin filled in the luminal space: (B) hematoxylin and eosin, 100×. Immunohistochemical study with CD-34 illustrates positive staining with the normal vascular structure, but not the lining of the pseudoglandular structure of the tumor cell nests, a differential diagnosis from the angiosarcoma: (C) 40×. The resected specimen revealed an ulcerative lesion 6 cm × 4 cm × 3.5 cm, which extended to the maxillary sinus and bone, the infraorbital rim, ethmoid sinus, nasal mucosa, and conchae. Unfortunately, the safe margin was close to the section surface of the tumor. (D) The submandibular gland and all of the lymph nodes were free of tumor cell invasion.

Table 1

Intraoral acantholytic squamous cell carcinoma patients.

Authors	Age (y)	Sex	Location	Lesion	LN meta	Recurrence (mo)	Follow up (mo)
Goldman et al2	61	M	Tongue	Nodular Ulcerated	Absent	4	DOD/8 mo
Takagi et al5	50	F	Maxillary gingiva	Ulcerated	Present	24	DOD/36 mo
Takagi et al5	56	M	Tongue	Erosion Ulcerated	Present	30	DOD/45
Zaatari and Santoianni6	86	M	Mandibular gingiva	Nodular	Present	No data	DOD/0
Jones et al7	58	M	Mouth floor	Exophytic verrucous	Absent	NED	NED/8
Kusafuka et al8	64	F	Mouth floor	Tumor	Present	NED	NED/5
Zidar et al9	59	M	Buccal mucosa	Ulcerated tumor	Absent	NED	NED/20
Zidar et al9	77	F	Mouth floor	tumor	Absent	NED	NED/16
Driemel et al10	57	M	Tongue	No data	Absent	No data	No data
Driemel et al10	68	M	Tongue	No data	Absent	No data	No data
Driemel et al10	50	M	Mouth floor	No data	Present	No data	No data
Kerawala11	56	M	Tongue	Ulcerated tumor	Absent	5	DOD/3
Papadopoulou et al4	72	F	Maxillary gingival	Ulcerated tumor	Present	10	DOD 7
Present case	55	M	Soft palate	Ulcerated	Absent	12	NED

DOD = died of disease; F = female; LN = lymph node; M = male; NED = no evidence of disease.

Table 2

Upper aerodigestive tract acantholytic squamous cell carcinoma patients.

Authors	Age (y)	Sex	Location	Lesion	LN meta	Recurrence	Follow up
Zaatari and Santoianni6	42	M	NPC	Ulcerated	Present	No	NED/18 mo
Hertenstein12	63	M	Larynx	No data	No data	No data	No data
Krecicki3	64	M	Larynx	No data	No data	No data	No data
Gonzalez-vela et al3	75	M	Larynx	Exophytic	Present	2 mo	DOD/9 mo

DOD = died of disease; LN = lymph node; M = male; NED = no evidence of disease.

ASCC is an uncommon but well-recognized variant of SCC characterized by marked acantholysis in the cancer nests leading to a pseudoglandular appearance. The first description of a case of intraoral ASCC, reported by Goldman et al in 1977, was of a 61-year-old man with an ulcerated lesion on the right tongue border, which was subsequently treated with radiation and surgical excision. According to previous literature, 13 cases of intraoral ASCC have been presented. Our present case was the 14th in oral mucosa membranes and the first to report ASCC affecting the soft palate (Table 1, Table 2). Intraoral ASCC should be differentiated from angiosarcoma; ASCC may be effectively distinguished from angiosarcoma by appropriate immunohistochemical studies such as CD31 and CD34, (Figure 1c), and von Willebrand factor. Loss of E-cadherin has been associated with an unfavorable prognosis. Loss of E-cadherin and syndecan-1 is suggestive of dyscohesion of cancer cells which is thought to promote invasion. Therefore, postoperative concurrent chemoradiotherapy and long term follow up should be considered (Figure 1).

In conclusion, a literature review revealed that ASCC has been an expression for aggressive invasion and metastasis to the lymph nodes.4, 10 A suggested treatment protocol includes wide excision with prophylactic neck dissection, and postoperative adjuvant radiotherapy with chemotherapy where necessary.

Conflicts of interest

The authors have no conflicts of interest relevant to this article.