Report of Two Cases of Combined Odontogenic Tumors: Ameloblastoma with Odontogenic Keratocyst and Ameloblastic Fibroma with Calcifying Odontogenic Cyst.

Combined odontogenic neoplasms have rarely been documented. Such tumors have also been described by other researchers as "hybrid" lesions. The histologic features are often identical to other individually well-established odontogenic neoplasms such as ameloblastoma, adenomatoid odontogenic tumor, ameloblastic fibroma (AF), and ameloblastic fibro-odontoma. Their clinical presentation is variable, ranging from cysts to neoplasms showing varying degrees of aggressive behavior. Most combined tumors contain features of one of the odontogenic tumors in combination with either a calcifying odontogenic cyst (COC) or a calcifying epithelial odontogenic tumor. We present two new cases of combined odontogenic tumors: an ameloblastoma with an odontogenic keratocyst and an AF with COC. Predicting clinical outcome is challenging when a combination tumor is encountered due to the paucity of such lesions. One must understand salient features of these entities and differentiate them from the more common conventional neoplasms to expand classification and provide prognostic criteria.

Papillary variant of squamous cell carcinoma arising on the gingiva: 61 cases reported from within a larger series of gingival squamous cell carcinoma.

Papillary squamous cell carcinoma (PSCCA) is a rarely occurring variant of squamous cell carcinoma (SCCA) with distinctive exophytic and papillary features and a more favorable prognosis than conventional SCCA. The larynx is the most commonly affected site in the head and neck. The oral cavity, oropharynx, sinonasal tract, and nasopharynx are also affected. Within the oral cavity cases have been reported on the alveolar ridge, oral mucosa, floor of the mouth, ventral tongue, and rarely other areas. We identified 61 cases of gingival PSCCA within the parameters of a larger study of 519 cases of gingival SCCA. We evaluated the clinical and histologic features of these lesions. The average age of the PSCCA patient was 74 years, with a very slight male predominance of 1.2:1. The mandible was affected nearly twice as often (64 %, n = 39) as the maxilla (35 %, n = 21, and 1 % of cases unspecified), and the most common location by far was the mandibular posterior region (52 %, n = 32). Most lesions were reportedly present over 2 months in duration (48 %, n = 29) prior to biopsy but a significant amount of clinicians were unsure of the duration of the lesion as well (36 %, n = 22). Only 10 cases (16 %) were reportedly present less than 2 months. The most common clinical presentation was that of an erythematous or mixed white and red exophytic mass (74 %, n = 45). 62 % (n = 38) of submitting clinicians considered a malignant or premalignant lesion in their differential diagnosis, but other clinical impressions included papillomas, reactive gingival lesions, and fungal infections. Histologically, 88 % (n = 52 of 59 cases graded) of the lesions were either well or moderately-well differentiated. PSCCA is a rare subtype of SCCA which has been reported infrequently involving the gingiva or alveolar ridges but should be considered by clinicians for the differential diagnosis of papillary gingival masses.

The clinical and histologic presentation of gingival squamous cell carcinoma: a study of 519 cases.

OBJECTIVES: Gingival squamous cell carcinoma (SCCA) often presents with benign features, which may lead to delay in treatment. This study describes the clinical and histologic characteristics of a series of gingival SCCA cases. STUDY DESIGN: A retrospective consecutive case review was performed using the University of Florida College of Dentistry Biopsy service's database, which yielded clinical and histologic information on 519 cases of gingival SCCA. RESULTS: The average age of affected patients was 72.3 years. The most common site was the mandibular posterior gingiva. Approximately 72% of lesions were present for >2 months at biopsy. The majority of clinicians considered a malignancy in their differential diagnosis (64%), although 15% considered only reactive lesions. Most of the carcinomas presented as exophytic masses and, histologically, were moderately differentiated. CONCLUSIONS: Gingival SCCA may present with varied clinical and histologic appearances and should be considered in the differential diagnosis of benign appearing lesions of the gingiva.

Protein storage and root:shoot reallocation provide tolerance to damage in a hybrid willow system.

To determine the mechanistic basis of tolerance, we evaluated six candidate traits for tolerance to damage using F(2) interspecific hybrids in a willow hybrid system. A distinction was made between reproductive tolerance and biomass tolerance; reproductive tolerance was designated as a plant's proportional change in catkin production following damage, while biomass tolerance referred to a plant's proportional change in biomass (i.e., regrowth) following damage. F(2) hybrids were generated to increase variation and independence among candidate traits. Using three clonally identical individuals, pre-damage candidate traits for tolerance to damage (root:shoot ratio, total nonstructural carbohydrate, and total available protein) and post-damage candidate traits (relative root:shoot ratio, phenolic ratio, and specific leaf area ratio) were measured. The range of variation for these six candidate traits was broad. Biomass was significantly increased two years after 50% shoot length removal, and catkin production was not significantly reduced when damaged, suggesting that F(2) hybrids had great biomass tolerance and reproductive tolerance. Based on multiple regression methods, increased reproductive tolerance was associated with increased protein storage and decreased relative root:shoot ratio (reduced root allocation after damage). In addition, a positive relationship between biomass tolerance and condensed tannins was detected, and both traits were associated with increased reproductive tolerance. These four factors explained 57% of the variance in the reproductive tolerance of F(2) hybrids, but biomass tolerance explained the majority of the variance in reproductive tolerance. Changes in plant architecture in response to plant damage may be the underlying mechanism that explains biomass tolerance.