Head and Neck Pathology

PTEN hamartoma tumor syndrome refers to a spectrum of disorders caused by mutations in the phosphatase and tensin homolog (PTEN) gene. Cowden syndrome, the principal PTEN-related disorder is characterized by multiple neoplasms and hamartomas, mucosal papillomatosis, and skin lesions, trichilemmomas. Trichilemmomas and mucocutaneous papillomatous papules are one of the first signs of the disease. Early recognition of these skin lesions may help on diagnosing an underlying malignancy and early cancer screening.

Hyalinizing clear cell carcinoma (HCCC) is an extremely rare neoplasm with a female predominance, composed of nests of monomorphic clear cells within a hyaline stroma. This tumor often follows an indolent course and treatment includes wide surgical excision with or without adjuvant radiotherapy. We report eight cases of HCCC identified at two academic institutions in six women and two men, ranging in age from 25 to 86 years. Histologically, all cases demonstrated cords, trabeculae, and nests of monomorphic clear cells as well as cells with eosinophilic granular cytoplasm. Mild cellular atypia was occasionally seen and mitoses were very rare. Seven cases demonstrated a hyalinized stroma, and one case, a myxoid stroma. Immunohistochemically, the tumor cells were positive for epithelial markers and negative for desmin and actin. Seven cases were negative for S-100. Cells were also positive for periodic acid-Schiff and negative for mucin. The important clinicopathologic features and the differential diagnoses of HCCC, as well as a review of the literature are discussed.

CT and MR imaging are essential cross-sectional imaging modalities for assessment of temporal bone anatomy and pathology. The choice of CT versus MR depends on the structures and the disease processes that require assessment, delineation, and characterization. A thorough knowledge of the two imaging modalities’ capabilities and of temporal bone anatomy greatly facilitates imaging interpretation of pathologic conditions.

Differentiating adenoid cystic carcinoma (AdCC) from other basaloid neoplasm in a fine needle aspiration (FNA) sample can be challenging. Activation of MYB in AdCC by the fusion transcript MYB-NFIB has been recently demonstrated in salivary gland and other organs. The aim of this study is to evaluate the utility of MYB immunohistochemistry (IHC) in distinguishing AdCCs and other basaloid neoplasm in cytology specimens. Eighteen FNA cases, from salivary gland and other sites, and their subsequent surgical resection specimens were included in the study. Eight cases were confirmed AdCC on resection. MYB IHC was performed on slides made from cytology cell block and surgical resection paraffin blocks. Percentage and intensity of nuclear staining in tumor cells was scored as 0 to 3. The staining results were concordant between cytology specimens and their corresponding surgical resection tumors. Strong diffuse nuclear staining (score 3, N = 5) was exclusively observed in AdCC, both in cytology and surgical specimens. Only one pleomorphic adenoma and one poorly differentiated basaloid carcinoma were positive for MYB staining (score 1 to 2). Any degree of nuclear MYB labeling was seen in 100% AdCC cases (N = 8/8) compared with of 20% (N = 2/10) of all other non-AdCC cases (P = < 0.001). The sensitivity and specificity of any degree MYB positivity for AdCC in cytology specimen is 100% and 78%. The sensitivity and specificity of strong diffuse MYB labeling (score 2 to 3) for AdCC is 83% and 100% in cytology specimen. Strong diffuse nuclear staining of MYB is valuable in supporting a cytologic diagnosis of AdCC. However, weak and focal labeling of MYB should be interpreted with caution as it can be seen in benign and other malignant basaloid lesions.

Head and neck rhabdomyosarcoma occurs frequently in children and adolescents, and has been well studied in that population. In contrast, it is rare in adults and is not as well characterized clinically and pathologically. Seven cases of adult rhabdomyosarcoma occurring in head and neck were retrieved from the archives of Department of Pathology and Division of Oral Pathology at University of Washington. Radiologic findings and clinical history, as well as pathologic findings from hematoxylin and eosin slides and immunohistochemistry for myogenic markers were reviewed. A total of seven cases of rhabdomyosarcoma (two embryonal, three alveolar and two pleomorphic subtype) were reviewed. Patient ages ranged from 18 to 57 years (median 21 years). Classic and unique histologic features for each subtype, including post-treatment morphologic changes, were identified. Clinical follow-up information was available for 4 patients. 3 of 4 patients experienced recurrence, including two with distant metastasis. One patient died of disease progression 41 months after presentation. Head and neck rhabdomyosarcoma in adults can manifest both classic and unique histologic features for each subtype. In addition, recurrence and distant metastasis were observed, suggesting aggressive clinical behavior regardless of subtype.

The perineurioma is an infrequently encountered benign peripheral nerve sheath tumor composed of a clonal proliferation of perineurial cells. Rare cases of perineurioma have been reported in the oral cavity. An extraneural sclerosing perineurioma arising in the buccal mucosa of a 17-year-old male is presented. Histopathologically, the tumor is composed of a well circumscribed nodular proliferation of spindle cells arranged in a storiform growth pattern, in some areas subtly arranged around vascular channels. The tumor cells reveal positive immunostaining for epithelial membrane antigen (EMA), collagen type IV and vimentin, and negative immunostaining for S-100 protein, consistent with a perineurial origin. To the best of our knowledge, this case represents the first report of an extraneural sclerosing perineurioma involving the oral cavity.

In a previous study, we found interobserver agreement among 88 board-certified pathologists evaluating perineural invasion (PNI) in oral squamous cell carcinoma (OSCC) was fair, and participants most often used the following criteria: (1) tumor invading the perineurium, (2) tumor surrounding a nerve. In this study, we aimed to determine whether application of these most commonly used criteria may improve interobserver agreement. 512 pathologists were invited to participate in a web-based survey. Participants were asked to assess the presence/absence of PNI in a set of OSCC photomicrographs by applying each of the two criteria above. The survey was completed by 84 board-certified pathologists [mean age: 52 years (range 31–81), mean years in practice: 19 (range 1–56)]. Interobserver agreement was moderate (k = 0.46, 95% CI 0.45–0.46) when using definition #1 (tumor invading the perineurium) and fair (k = 0.24, 95% CI 0.23–0.25) when using definition #2 (tumor surrounding a nerve). By comparison, interobserver agreement was fair (k = 0.36, 95% CI 0.35–0.37) among phase 1 participants asked to evaluate these photomicrographs as they would in their pathology practice. Differences in kappa between definition #1 and phase 1, definition #2 and phase 2, and definition #1 and #2 were statistically significant (p < 0.001). Compared to our prior study based on pathologists’ personal views, the current study shows improved interobserver agreement with application of the criterion, “tumor invading the perineurium.” However, further work is needed to delineate concise, objective, and more reproducible criteria for histopathologic assessment of PNI.

Dermal filler injections are common cosmetic procedures and are growing in popularity. While frequently performed, dermal filler injections carry a risk of adverse events including vascular compromise and foreign body granulomas. Here, we discuss an unusual case of a patient with a history of dermal filler injections presenting with a parotid mass and an eyebrow mass requiring surgical resection. This case demonstrates the risk of delayed granuloma formation many years after dermal filler injection and highlights the importance of awareness and management of these potential long-term complications.

Oral hairy leukoplakia (OHL) is an Epstein-Barr virus (EBV) related lesion seen in severely immunocompromised patients especially, those with concomitant human immunodeficiency virus (HIV) infection. It has been rarely reported in immunocompetent patients. OHL most often presents on the lateral border of the tongue as an asymptomatic, white, and corrugated plaque that does not rub off. With Institutional Review Board (IRB) approval, the University of Florida Oral & Maxillofacial Pathology Biopsy Service archives spanning 1994–2020 were queried. All cases of OHL affecting immunocompetent patients were identified. Data related to age, gender, clinical presentation, results of Epstein-Barr virus in situ hybridization (EBER-ISH), and periodic acid–Schiff (PAS)-fungus stains were recorded. Medical history and histology of all cases were reviewed for confirmation of diagnosis. A total of 11 cases were identified, the majority of which were males (63.6%) with a mean age of 62 years. All patients were Caucasian. Lesions entirely were located on the lateral borders of the tongue. OHL should not be considered pathognomonic for HIV infection and should be included in the differential diagnoses of keratotic lesions affecting the lateral border of tongue even in immunocompetent elderly patients. The etiology of OHL in this group of patients is not clearly understood.

Noonan-like/multiple giant cell lesion syndrome (NS/MGCLS) is a rare condition with phenotypic overlap with Noonan syndrome (NS). Once thought to be a specific and separate entity, it is now suggested to be a variant of the NS spectrum. We report a patient with classical cardinal features of NS, including short stature, mild ptosis, hypertelorism, down-slating palpebral fissures, low-set and posteriorly angulated ears, short neck, pectus excavatum, widely spaced nipples and cryptochidism, which were associated with bilateral central giant cell lesions in the mandible and germ-line mutation (C218T, Thr73Ile) in the exon 3 of the PTPN11 gene. The similar clinical and genetic aspects support the observation that NS/MGCLS is a variant of NS and giant cell lesions are an integrant part of this disorder.