We used an antibody array to compare the protein expression of matrix metalloproteinases (MMPs)-1, -2, -3, -8, -9, -10, and -13, as well as the tissue inhibitors of metalloproteinases (TIMPs)-1, -2, and -4 during blastema formation in amputated hindlimbs of regeneration-competent wild-type axolotls and stage-54 Xenopus, and regeneration-deficient short-toes axolotls and Xenopus froglets. Expression of MMP-9 and -2 was also compared by zymography. Both short-toes and froglet failed to up-regulate MMPs in a pattern comparable to the wild-type axolotl, suggesting that subnormal histolysis is at least in part responsible for the poor blastema formation characteristic of both short-toes and froglet. MMP levels were much lower in amputated stage-54 Xenopus limb buds than in the other animals, suggesting that blastema formation in these limb buds requires much less extracellular matrix degradation than in fully differentiated limbs. TIMP expression patterns followed the same trends as the MMP's in each group of animals. Developmental

Calcifying epithelial odontogenic tumor (CEOT) is an uncommon locally invasive epithelial odontogenic tumor of the jaws associated with amyloid production. Intraosseous presentations are most common and they frequently occur in the posterior mandible. A non-calcifying Langerhans cell-rich variant of CEOT (NCLC CEOT) has been described with predilection for the anterior maxilla. Interestingly, all reported cases of NCLC CEOT have occurred in Asian population. We present a case of a 43-year old Caucasian female with a large radiolucent lesion involving the left anterior maxilla with histologic features of NCLC CEOT. This is the first reported case of this rare variant of CEOT in a Caucasian individual.

Chronic sclerosing sialadenitis (CSS) is a benign chronic inflammatory condition of the salivary gland. Clinically, CSS patients may present with a neck mass, often suggesting a neoplastic process. Fine-needle aspiration (FNA) is frequently used to evaluate these lesions. We present a series of 4 patients with CSS, in whom all but one had history of squamous cell carcinoma. The previous diagnosis of malignancy appeared to influence the interpretation of the cytologic preparations. Four patients who had undergone resection of a neck nodule that eventually was diagnosed as CSS were identified. FNA was performed in all 4 cases, and the final cytologic diagnosis in these cases included squamous cell carcinoma, basaloid neoplasm, and salivary gland neoplasm. During intraoperative consultation, the lesions were identified as benign, atrophic salivary gland with chronic inflammation, or sialadenitis with atypical glands. All resected specimens were submitted for histopathological examination and were considered diagnostic for CSS. CSS is a potential pitfall in the FNA interpretation of salivary gland lesions, especially if there is a previous history of head and neck malignancy. Awareness of this entity, adherence to strict cytologic criteria, and careful clinicopathologic correlation are helpful in preventing misinterpretation and unnecessary surgical intervention.

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