Tyrosine-rich crystals in pleomorphic adenomas of parotid glands

Tyrosine-Like Crystalloids Localize to Non-Neoplastic True Vocal Cord and Attachments

BACKGROUND

Tyrosine-rich or tyrosine-like crystalloids (TC) were initially described in salivary gland pleomorphic adenoma. The presence of TC in non-neoplastic tissues is rare, and it has been reported exclusively in the larynx. This study aims to characterize the frequency and anatomical localization of TC in total laryngectomy specimens.

METHODS

Review of consecutive laryngectomy specimens in which the cassette summary documented parasagittal section sampling of the right and left vocal folds and the anterior commissure. Data collected included patient demographics, underlying diagnoses, history of radiation therapy, presence, and location of TC.

RESULTS

Of 86 laryngectomy specimens, 16 (19%) contained amphophilic to eosinophilic TC. The study cohort included 11 males and 5 females, aged 37 to 85 years (mean 62, median 63). Laryngectomy surgery was performed for advanced untreated squamous cell carcinoma (SCCa) (7/16, 43.75%), recurrent post-treatment SCCa (7/16, 43.75%), previously untreated laryngeal large cell neuroendocrine carcinoma (1/16, 6.25%), and non-functional larynx post-chemoradiation (1/16, 6.25%). According to the macroscopic cassette summary, TC were predominantly found in the anterior commissure Sect. (13/16, 81.25%), with fewer cases in sections containing the left (2/16, 12.5%) or the right (1/16, 6.25%) vocal folds. Microscopically, TC localized to the anterior macula flava and/or adjacent vocal ligament (12/16, 75%) and the anterior commissure tendon (4/16, 25%).

CONCLUSIONS

TCs are predominantly reported as admixed with a neoplasm, however this study confirms that TC can also occur in non-neoplastic tissues of the larynx. There was no clear relationship between the presence of TC and prior radiation therapy. TC in the specialized connective tissues of the macula flava and true cord tendinous insertions distinct from tumor may form in response to alterations in mechanical stress, though an age-related change within the spectrum of normal laryngeal microanatomy also remains a possibility.

Differentiation of Salivary Gland and Salivary Gland Tumor Tissue via Raman Imaging Combined with Multivariate Data Analysis

Salivary gland tumors (SGTs) are a relevant, highly diverse subgroup of head and neck tumors whose entity determination can be difficult. Confocal Raman imaging in combination with multivariate data analysis may possibly support their correct classification. For the analysis of the translational potential of Raman imaging in SGT determination, a multi-stage evaluation process is necessary. By measuring a sample set of Warthin tumor, pleomorphic adenoma and non-tumor salivary gland tissue, Raman data were obtained and a thorough Raman band analysis was performed. This evaluation revealed highly overlapping Raman patterns with only minor spectral differences. Consequently, a principal component analysis (PCA) was calculated and further combined with a discriminant analysis (DA) to enable the best possible distinction. The PCA-DA model was characterized by accuracy, sensitivity, selectivity and precision values above 90% and validated by predicting model-unknown Raman spectra, of which 93% were classified correctly. Thus, we state our PCA-DA to be suitable for parotid tumor and non-salivary salivary gland tissue discrimination and prediction. For evaluation of the translational potential, further validation steps are necessary.

Rare Floret Like Tyrosine Crystals in Pleomorphic Adenomas of Parotid Gland

The pleomorphic adenoma arising in the parotid gland is a benign neoplasm that is aptly named because of its histomorphological diversity. The stromal component can contain chondromyxoid material, amyloid, and elastic fibers, along with a few rare reports of crystalline structures present in this tumor. Especially, the crystalline components are rarely encountered or appreciated in routine pathology reporting. Here, we report a case of pleomorphic adenoma of the parotid gland, in which tyrosine-rich crystalloids were identified in abundance and were confirmed with special stains and electron microscopy. Though their exact source is not yet known, crystallization of the stromal or myoepithelial cell secretion has been hypothesized. This comprehensive report is to make the histopathologists aware of this rare morphological observation in pleomorphic adenomas so that more cases are identified and followed-up to reveal the impact of their presence in a subset of pleomorphic adenomas.

Crystals and crystalloids in cytopathology: Incidence and importance

Many crystals and crystal-like structures may be encountered in cytopathology practice and can represent both beautiful novelties and diagnostic aids. The authors present an organ-specific review of the published literature on crystals combined with personal experiences. The purpose is not only to serve as a reference guide by highlighting the clinical and morphologic features of crystals, crystalloids, and crystal-like structures but also to review their significance and to offer reporting strategies in cases that bear management implications.

Chondroid syringoma with tyrosine crystals: case report and review of the literature

Chondroid syringoma (CS) is a relatively rare cutaneous mixed tumor arising from sweat glands. It usually presents in the head and neck area as an asymptomatic, slow-growing, firm, circumscribed, lobulated nodule within the dermis or subcutaneous fat. CSs share morphologic similarities with their salivary gland counterparts, pleomorphic adenomas (benign mixed tumors). Although the presence of tyrosine-rich crystalloids in mixed tumors of the salivary gland is well recognized, to our knowledge, this finding has not been previously described in mixed tumors of the skin. We report a case of tyrosine crystalline structures in a CS and review the pertinent literature.

Tyrosine-rich crystalloids in a polymorphous low-grade adenocarcinoma

A polymorphous low-grade adenocarcinoma with tyrosine-rich crystalloid deposits is reported. The literature is reviewed, and diagnostic and histogenetic implications of this finding are discussed.

Tyrosine-rich crystalloids in pleomorphic adenoma: SEM findings and partial biochemical characterization

The rare tyrosine-rich crystalloids (TRC) of salivary gland pleomorphic adenoma (PA) give a positive Million reaction indicating the presence of tyrosine. Their varied histochemical reactions, however, suggest a more complex composition. Two cases of TRC were encountered in a series of 144 PA (1.4%). Both were studied with several histochemical stains, and one tumor particularly rich in TRC was further examined with transmission and scanning electron microscopy and subjected to biochemical analysis using fresh-frozen tissue. TEM showed amorphous, electron-dense masses with no discernable internal structure. SEM revealed a geodelike structure of radially arranged, interlocking plates. Amino acid analysis of normal parotid, tumor with TRC, and a similar tumor without TRC indicated a slightly elevated level of tyrosine and arginine in the tumor with TRC. Polyacrylamide gel electrophoresis of tissue dissolved in sodium dodecyl sulfate revealed dense banding corresponding to polypeptides of a relative molecular weight of approximately 17,000 only in the TRC-rich sample. These bands on further analysis contained relatively large amounts of arginine. Tyrosine was present in only small amounts. TRC appear to be small proteins containing some tyrosine but rich in arginine.

Intraluminal crystalloids in malignant salivary gland tumors (electron microscopic and X-ray microanalytic studies)

The ultrastructural, X-ray microanalytical, histochemical and immunocytochemical features of intraluminal crystalloids found in adenocarcinomas of the parotid gland have been studied. The crystalloids, putatively derived from an abnormal crystalization of salivary duct proteins, are considerably different from the crystalloids found in normal parotid glands, pleomorphic adenomas, and sialocysts.