Superficial fibromas with CTNNB1 mutation.

Superficial fibromas are a group of mesenchymal spindle cell lesions with pathomorphological heterogeneity and diverse molecular backgrounds. In part, they may be indicators of an underlying syndrome. Among the best-known entities of superficial fibromas is Gardner fibroma, a plaque-like benign tumor, which is associated with APC germline mutations and occurs in patients with familial adenomatosis polyposis (Gardner syndrome). Affected patients also have an increased risk to develop desmoid fibromatosis (DTF), a locally aggressive neoplasm of the deep soft tissue highly prone to local recurrences. Although a minority of DTFs occur in the syndromic context and harbor APC germline mutations, most frequently their underlying molecular aberration is a sporadic mutation in Exon 3 of the CTNNB1 gene. Up to date, a non-syndromic equivalent to Gardner fibroma carrying a CTNNB1 mutation has not been defined. Here, we present two cases of (sub-)cutaneous tumors with a hypocellular and collagen-rich Gardner fibroma-like appearance and pathogenic, somatic CTNNB1 mutations. We aim to differentiate these tumors from other fibromas according to their histological appearance, immunohistochemical staining profile and underlying somatic CTNNB1 mutations. Furthermore, we distinguish them from locally aggressive desmoid fibromatosis regarding their biological behavior, prognosis and indicated therapeutic strategies. Consequently, we call them CTNNB1-mutated superficial fibromas as a sporadic counterpart lesion to syndromic Gardner fibromas.

When molecular outsmarts morphology: Malignant ossifying fibromyxoid tumors masquerading as osteosarcomas, including a novel CREBZF::PHF1 fusion.

We present two cases of malignant ossifying fibromyxoid tumor (OFMT) which eluded diagnosis due to compelling clinicopathologic mimicry, compounded by similarly elusive underlying molecular drivers. The first is of a clavicle mass in a 69 year-old female, which histologically showed an infiltrative nested and trabeculated proliferation of monomorphic cells giving rise to scattered spicules of immature woven bone. Excepting SATB2 positivity, the lesion showed an inconclusive immunoprofile which along with negative PHF1 FISH led to an initial diagnosis of high-grade osteosarcoma. Next generation sequencing (NGS) revealed a particularly rare CREBBP::BCORL1 fusion. The second illustrates the peculiar presentation of a dural-based mass in a 52 year-old female who presented with neurologic dyscrasias. Sections showed a sheeted monotonous proliferation of ovoid to spindle cells, but in contrast to Case #1, the tumor contained an exuberance of reticular osteoid and woven bone deposition mimicking malignant osteogenic differentiation. NGS showed a novel CREBZF::PHF1 fusion. Both tumors recurred locally less than 1 year post-operatively. As such we reiterate that careful morphologic examination is axiomatic to any diagnosis in our discipline, but this paradigm must shift to recognize that molecular diagnostics can provide closure where traditional tools have notable limitations.

Recurrent FOSL1 rearrangements in desmoplastic fibroblastoma.

The FOS gene family has been implicated in tumourigenesis across several tumour types, particularly mesenchymal tumours. The rare fibrous tumour desmoplastic fibroblastoma is characterised by overexpression of FOSL1. However, previous studies using cytogenetic and molecular techniques did not identify an underlying somatic change involving the FOSL1 gene to explain this finding. Prompted by an unusual index case, we report the discovery of a novel FOSL1 rearrangement in desmoplastic fibroblastoma using whole-genome and targeted RNA sequencing. We investigated 15 desmoplastic fibroblastomas and 15 fibromas of tendon sheath using immunohistochemistry, in situ hybridisation and targeted RNA sequencing. Rearrangements in FOSL1 and FOS were identified in 10/15 and 2/15 desmoplastic fibroblastomas respectively, which mirrors the pattern of FOS rearrangements observed in benign bone and vascular tumours. Fibroma of tendon sheath, which shares histological features with desmoplastic fibroblastoma, harboured USP6 rearrangements in 9/15 cases and did not demonstrate rearrangements in any of the four FOS genes. The overall concordance between FOSL1 immunohistochemistry and RNA sequencing results was 90%. These findings illustrate that FOSL1 and FOS rearrangements are a recurrent event in desmoplastic fibroblastoma, establishing this finding as a useful diagnostic adjunct and expanding the spectrum of tumours driven by FOS gene family alterations. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Elastofibromatous changes in giant cell fibroma and amalgam tattoo: Unusual findings in common oral lesions.

Several cases of elastofibromatous lesion affecting the oral mucosa have been reported. Clinically, these lesions may appear as small exophytic lesions or less often as white lesions. Therefore, fibrous hyperplasia and leukoplakia are not uncommonly considered in clinical differential diagnosis. Microscopically, elastic and fibrous connective tissue deposition is seen. Rarely, elastofibromatous changes can be detected when assessing intraoral lesions, including cysts, salivary gland neoplasms, and epithelial dysplasia. Here we report two oral lesions showing elastofibromatous changes, expanding their clinicopathological spectrum. The first case was a 46-year-old man with a history of asymptomatic nodular lesion on the palate 1 year ago, diagnosed as giant cell fibroma with elastofibromatous changes. The second case was a 79-year-old woman who presented a pigmented and mildly symptomatic lesion on the mandibular alveolar mucosa several months ago, diagnosed as amalgam tattoo associated with elastofibromatous changes.

What is in a name-Perifollicular fibroma or fibrofolliculoma?

So far, confusion exists regarding the question of whether hereditary perifollicular fibromas and fibrofolliculomas can be distinguished from each other. Here, histopathological arguments are presented to clarify this terminological problem. In 1977, Birt et al. described a large kindred affected with hereditary multiple "fibrofolliculomas," which they thought were "a hitherto unrecognized pilar hamartoma," but they never claimed the fibrofolliculomas were part of a syndrome. A careful microscopic comparison shows, however, that the tumors are clinically and histopathologically identical to perifollicular fibromas, as first described by Burnier and Rejsek in 1925. Their familial occurrence was discovered in 1971 by Civatte and Le Tréguilly. Before 1977, the term "perifollicular fibroma" was used for these skin tumors. By contrast, Hornstein and Knickenberg described in 1975 perifollicular fibromas as a cutaneous marker of a syndrome characterized by a predisposition to colon cancer and pneumothorax. Later, two French groups erroneously proposed the term "Birt-Hogg-Dubé syndrome" to describe the co-occurrence of fibrofolliculomas, trichodiscomas, and acrochordons, which was contrary to what Birt et al. had in mind. Hence, today, we should discriminate between the hereditary nonsyndromic perifollicular fibromas, as documented by Civatte and Le Tréguilly and later by Birt et al., and the syndromic perifollicular fibromas, as delineated by Hornstein and Knickenberg.

Superficial desmoplastic fibroblastoma (collagenous fibroma): Clinicopathologic study of 11 cases.

BACKGROUND: Desmoplastic fibroblastoma (collagenous fibroma) is a rare soft tissue tumor that usually arises in the subcutis or skeletal muscle. Cases superficial to fascia are unusual and can cause diagnostic difficulty. We present 11 cases of superficial desmoplastic fibroblastoma involving a wide anatomic distribution. METHODS: Archives were searched using the term "desmoplastic fibroblastoma" over a 10-year period (2012-2022). Cases superficial to fascia were retrieved, and available clinicopathologic features were recorded. Only cases involving the dermis were included. RESULTS: Eleven cases were identified, all of which were received in consultation. Tumors involved the head and neck (2), lower extremity (2), back (2), foot (1), shoulder (1), axilla (1), hand (1), and breast (1). Each consisted of a hypocellular proliferation of bland stellate to spindled fibroblasts set in a collagenous to focally myxoid stroma. The immunohistochemical stains available for review demonstrated SMA positivity (4/7) and negative immunoreactivity for CD34 (0/6), EMA (0/3), desmin (0/3), and S100 (0/7). CONCLUSIONS: Desmoplastic fibroblastoma may present superficially in the dermis to subcutis, posing a potential source of diagnostic difficulty. Recognition of the characteristic histopathologic features of desmoplastic fibroblastoma with judicial use of immunohistochemical stains should allow for accurate diagnosis.

Giant cell collagenoma in a patient with Cowden syndrome: A rare case report and literature review with a focus on the spectrum of sclerotic fibroma and giant cell collagenoma.

Sclerotic fibroma (SF) is a rare subset of dermal fibromas that occurs sporadically or in association with Cowden syndrome (CS). We report a case of a patient with known CS and a solitary lesion on the scalp. Histologic examination demonstrated a well-circumscribed lesion with sclerotic dermis and a whorled collagen pattern, multinucleated giant cells, and dendritic spindle cells. Nuclear atypia or mitotic figures were not noted. The giant cells were negative for Melan-A, SOX-10, EMA, SOX-10, and factor XIIIa. These findings are consistent with a giant cell collagenoma (GCC). Despite possible overlap with SF, GCC has not been associated with CS. This makes our case unique and suggests that GCC should be included in the spectrum of CS-associated cutaneous lesions. The diagnosis of SF may lead to the identification of previously undiagnosed CS; accordingly, GCC, even when present as a solitary lesion, may indicate the need for further work-up and screening for CS.

Giant cell collagenomas associated with Cowden syndrome: A case report.

Storiform collagenoma, also known as sclerotic fibroma, is a relatively rare benign cutaneous tumor consisting of a proliferation of fibroblasts that shows increased production of type I collagen. It may appear as a solitary, sporadic lesion, or, especially when multiple, associated with Cowden syndrome. Giant cell collagenoma has a histopathologic appearance similar to that of storiform collagenoma with the addition of floret-type giant cells. Herein, we report the finding of multiple giant cell collagenomas arising in an individual with Cowden syndrome. In a review of the published literature, this histopathologic variant appears to be rarely observed in association with Cowden syndrome.

Pediatric Plexiform Fibromyxoma: A Case Report.

The plexiform fibromyxoma is a rare mesenchymal tumor in adults that generally originates in the antrum of stomach, being its occurrence in pediatric patients exceptional. It was classified as a distinct entity by World Health Organization in 2010. No recurrences and metastases have been documented in many of the reported patients to date, being the surgical treatment curative. We report the case of a 3-month-old infant who presented to the emergency department with an episode of intestinal subocclusion requiring an emergent surgery. During the surgical intervention, a mass was identified in the jejunum, causing partial occlusion of its lumen. The surgical pathology report revealed an infiltrative tumor composed of spindle-shaped cells disposed in a stroma with a plexiform pattern alternating myxoid areas. These findings and the immunohistochemical characteristics of the neoplastic cells led to classify the tumor as a plexiform fibromyxoma. A description of the immunophenotype of this tumor is made and differential diagnosis with other gastrointestinal tumors is also discussed.

The mass that should not be there: Multi-modality imaging shapes diagnostic reasoning.

A rare case of pulmonary artery fibroelastoma that demonstrates the importance of multimodality imaging and serial scans in reducing diagnostic uncertainty.

Pediatric fibromyxoid brachial plexus tumor with YWHAZ::PLAG1 gene fusion: a case report.

Pediatric fibromyxoid soft tissue tumors may be associated with gene fusions such as YHWAZ::PLAG1, with only three reported cases in the literature. We present the fourth case, a 13-year-old male with a pediatric fibromyxoid brachial plexus tumor with YWHAZ::PLAG1 gene fusion. This is also the first case to be reported in an adolescent, in the brachial plexus, and in the Philippines. The patient presented with a 10-year history of a slowly growing left supraclavicular mass and a 1-year history of intermittent dysesthesia in the left upper extremity. Neurologic examination was unremarkable. Imaging revealed a large left supraclavicular lesion with intrathoracic extension. Surgical excision was performed, and histopathology revealed a fibromyxoid tumor with YWHAZ::PLAG1 gene fusion. Although previous examples of this gene fusion pointed toward lipoblastoma as their primary pathology, our tumor does not completely fulfill the current diagnostic criteria for a lipoblastoma and may represent an intermediate form of the disease. Our case is unique not only because it is the first reported adolescent patient harboring such a lesion but also because of the relatively lengthy natural history exhibited by the tumor prior to its resection. This provided us with valuable information about its behavior, which suggests a more indolent growth pattern. This case also highlights the clinical importance of molecular testing of tumors, where recognition of disease entities can assist clinicians in deciding and advocating for the proper management.

Histogenetic insights and genetic landscape of fibromatosis-like undifferentiated gastric carcinoma: a focused study.

BACKGROUND: The aim of this study was to elucidate the histogenesis and genetic underpinnings of fibromatosis-like undifferentiated gastric carcinoma (FLUGC), a rare pathological entity. METHOD: Through a detailed analysis of seven cases, including histopathological evaluation, CTNNB1 gene mutation screening, human epidermal growth factor receptor 2 (HER2) protein level quantification, and HER2 gene amplification assessment to identify the pathological and molecular characteristics of FLUGC. RESULTS: Of the seven patients in this study, five were male and two were female (age: 39-73 years). Four patients presented with lesions in the gastric antrum and three had lesions in the lateral curvature of the stomach. Histopathologically, over 90% of the tumor consisted of aggressive fibromatosis-like tissue, including proliferating spindle fibroblasts and myofibroblasts and varying amounts of collagenous fibrous tissues. Undifferentiated cancer cells, accounting for less than 10%, were dispersed among the aggressive fibromatosis-like tissues. These cells were characterized by their small size and were relatively sparse without glandular ducts or nested mass-like structures. Immunophenotyping results showed positive expression of CKpan, CDX2, villin, and p53 in undifferentiated cancer cells; positive expression of vimentin in aggressive fibromatosis-like tissue; positive cytoplasmic expression of ß-catenin; and focal cytoplasmic positive expression of smooth muscle actin (SMA). Genetic analysis did not reveal any mutations in the CTNNB1 gene test, nor was there amplification in the HER2 gene fluorescence in situ hybridization (FISH) test. Additionally, the Epstein-Barr encoding region (EBER) of in situ hybridization was negative; and the mismatch repair (MMR) protein was positive. Programmed cell death-1 (PD-1) was < 1-5%; programmed cell death ligand 1 (PD-L1): TPS = 1-4%, CPS = 3-8. CONCLUSION: The study highlights the significance of CTNNB1, HER2, EBER, and MMR as pivotal genetic markers in FLUGC, underscoring their relevance for diagnosis and clinical management. The rarity and distinct pathological features of FLUGC emphasize the importance of accurate diagnosis to prevent underdiagnosis or misdiagnosis and to raise awareness within the medical community.

Jaffe-Campanacci syndrome; a case series and review of the literature.

BACKGROUND: Jaffe-Campanacci syndrome is a rare syndrome, characterized by multiple non-ossifying fibromas (NOF) and cafe-au-lait patches. The name was coined in 1982 by Mirra after Jaffe who first described the case in 1958. Although it's suggested there is a relation with Neurofibromatosis type 1, there is still no consensus on whether Jaffe-Campanacci syndrome is a subtype or variant of neurofibromatosis-1(NF-1). CASE PRESENTATION: In this article, we present a case series of 2 patients. The first case is a 13-year-old male with Jaffe-Campanacci syndrome who presented with a distal femur fracture. His father had positive features of both Jaffe-Campanacci syndrome and NF-1, while his sister only had features of NF-1, so we presented both. CONCLUSION: Jaffe-Campanacci has a clear relationship with type 1 neurofibromatosis, which still has to be genetically established. Due to the presence of several large non-ossifying fibromas of the long bones, it is linked to a significant risk of pathological fractures. We concur with previous authors, that an osseous screening program should be performed for all patients with newly diagnosed type 1 neurofibromatosis, to identify non-ossifying fibromas and assess the potential for pathological fracture. Moreover, siblings of patients with NF-1 should be screened for multiple NOFs that may carry a high risk of pathological fractures.

Desmoplastic fibroma in a child: a 9-year follow-up case report.

BACKGROUND: Desmoplastic fibroma is an extremely rare primary bone tumor. Its characteristic features include bone destruction accompanied by the formation of soft tissue masses. This condition predominantly affects individuals under the age of 30. Since its histology is similar to desmoid-type fibromatosis, an accurate diagnosis before operation is difficult. Desmoplastic fibroma is resistant to chemotherapy, and the efficacy of radiotherapy is uncertain. Surgical excision is preferred for treatment, but it entails high recurrence. Further, skeletal reconstruction post-surgery is challenging, especially in pediatric cases. CASE PRESENTATION: Nine years ago, a 14-year-old male patient presented with a 4-year history of progressive pain in his left wrist. Initially diagnosed as fibrous dysplasia by needle biopsy, the patient underwent tumor resection followed by free vascularized fibular proximal epiphyseal transfer for wrist reconstruction. However, a histological examination confirmed a diagnosis of desmoplastic fibroma. The patient achieved bone union and experienced a recurrence in the ipsilateral ulna 5 years later, accompanied by a wrist deformity. He underwent a second tumor resection and wrist arthrodesis in a single stage. The most recent annual follow-up was in September 2023; the patient had no recurrence and was satisfied with the surgery. CONCLUSIONS: Desmoplastic fibroma is difficult to diagnose and treat, and reconstruction surgery after tumor resection is challenging. Close follow-up by experienced surgeons may be beneficial for prognosis.

Ovarian fibromatosis associated with large pedunculated fibroma in a 30-year-old woman: A rare coincidence or variant?

A 30-year-old nulligravida was referred under suspicion of large subserosal myoma. T2-weighted magnetic resonance imaging revealed multilobulated solid mass in the left lower abdomen measuring 16 cm in longitudinal diameter. The ovarian surface was covered with a marked T2-hypointense thick rim called "black garland sign," forming multiple nodular masses ranging from 1 to 5 cm in diameter in some portions of the bilateral ovaries. By laparoscopic-assisted minilaparotomy, the stalk of pedunculated mass originating from the left ovarian hilum was excised, followed by carrying out of the body after in-bag morcellation using a surgical scalpel. Right ovarian exophytic nodular masses larger than 1 cm were excised using monopolar electrode needle. Pathological examination of excised right and left masses showed fibroblast-like spindle cell proliferation with collagenous stroma; however, differences between right and left masses cannot be distinguished on a histological level. Postoperative diagnosis was ovarian fibromatosis coexisting with large pedunculated fibroma.

Rare cardiac tumour-nodular fasciitis.

Left ventricular tumour is a rare condition in children. The causes include vegetations, thrombus, and fibroma. 2-year-old asymptomatic female presented with an innocent heart murmur at 6 months of age. Subsequent follow-ups at 18 months of age showed left ventricular mass. Surgical pathology revealed "nodular fasciitis." This type of tumour has never been described in the heart before.

The Role of Surveillance in Predicting Fracture in Pediatric Patients With Incidentally Discovered Nonossifying Fibromas and Fibrous Cortical Defects: Is It Worth It?

BACKGROUND: Nonossifying fibroma (NOF) and fibrous cortical defect (FCDs), the most common benign pediatric bone lesions, are usually incidental x-ray findings. Surveillance of characteristic lesions has been recommended to monitor for enlargement and assess fracture risk. However, no accepted fracture risk prediction guidelines exist, so indications for prophylactic surgery are unclear. The study's purposes were to (1) characterize the timing of NOF/FCD-associated fractures, (2) quantify the resources devoted to surveillance, and (3) evaluate the potential for surveillance to prevent pathologic fracture. METHODS: A single institution retrospective review was conducted to identify pediatric patients (below 18 y old) with clinical-radiographic documentation of an NOF or FCD diagnosis from 2012 to 2020. Patients who presented with fracture were tallied but excluded from the surveillance analysis. Patients without at least one follow-up visit were also excluded. Lesional radiographic features were characterized on initial imaging. The number of visits and imaging studies devoted to surveillance were tabulated. The number of fractures and prophylactic surgeries were recorded to quantify the potential of surveillance to prevent pathologic fractures. RESULTS: The study population presenting without fracture consisted of 301 patients with 364 lesions with a mean follow-up of 20 months. By contrast, over the same period, 38 patients presented with NOF/FCD associated pathologic fractures. Surveillance included 1037 additional imaging tests over 1311 follow-up visits, or on average, 3.4 imaging studies and 4.4 visits per patient. During surveillance, only 2 (0.55%) lesions fractured. Another 10/364 (2.8%) patients underwent curettage and grafting, suggesting that-at best-the potential for preventing pathologic fracture by surveillance, assuming all 10 patients who underwent surgery would have subsequently fractured along with the 2 documented fractures, is 3.3% of lesions (12/364). CONCLUSIONS: The small number of fractures and surgeries during the follow-up period probably does not justify additional resources for surveillance beyond the initial visit, except in symptomatic patients with large lesions. However, subsequent visits may play a role in educating patients and their families regarding the natural history of these lesions. LEVEL OF EVIDENCE: Prognostic Level II-retrospective study.

Plexiform Fibromyxoma in the Stomach: Immunohistochemical Profile and Comprehensive Genetic Characterization.

Plexiform fibromyxoma (PF), also referred to as plexiform angiomyxoid myofibroblast tumor, is an exceedingly rare mesenchymal neoplasm primarily affecting the stomach. Herein, we present a case of PF diagnosed in a 71-year-old male with a history of lung cancer, initially suspected to have a gastrointestinal stromal tumor (GIST) of the stomach, who subsequently underwent subtotal gastrectomy. The histopathological and molecular features of the tumor, including mutations in ABL1, CCND1, CSF1R, FGFR4, KDR, and MALAT1-GLI1 fusion, are elucidated and discussed in the context of diagnostic, prognostic, and therapeutic considerations.

Insights into Hyperparathyroidism-Jaw Tumour Syndrome: From Endocrine Acumen to the Spectrum of CDC73 Gene and Parafibromin-Deficient Tumours.

A total of 1 out of 10 patients with primary hyperparathyroidism (PHP) presents an underlying genetic form, such as multiple endocrine neoplasia types 1, 2A, etc., as well as hyperparathyroidism-jaw tumour syndrome (HJT). We aimed to summarise the recent data, thus raising more awareness regarding HJT, from the clinical perspective of PHP in association with the challenges and pitfalls of CDC73 genetic testing and parafibromin staining. This narrative review included a sample-focused analysis from the past decade according to a PubMed search. We identified 17 original human studies (≥4 patients per article). The mean age at disease onset was between 20.8 and 39.5 years, while the largest study found that 71% of patients had HJT recognised before the age of 30. Males and females seemed to be equally affected, in contrast with sporadic PHP. PHP represented the central manifestation of HJT, occurring as the first manifestation in up to 85% of HJT cases. A biochemistry panel found a mean serum calcium level above the level of 12 mg/dL in PHP. PTH was elevated in HJT as well, with average values of at least 236.6 pg/mL. The most frequent pathological type in PHP was a parathyroid adenoma, but the incidence of a parathyroid carcinoma was much higher than in non-HJT cases (15% of all parathyroid tumours), with the diagnosis being established between the age of 15 and 37.5. In some families up to 85% of carriers suffered from a parathyroid carcinoma thus indicating that certain CDC73 pathogenic variants may harbour a higher risk. An important issue in HJT was represented by the parafibromin profile in the parathyroid tumours since in HJT both parathyroid adenomas and carcinomas might display a deficient immunoreactivity. Another frequent manifestation in HJT was ossifying fibromas of the jaw (affecting 5.4% to 50% of patients; the largest study found a prevalence of 15.4%). HJT was associated with a wide variety of kidney lesion (mostly: kidney cysts, with a prevalence of up to 75%, and renal tumours involved in 19% of patients). The risk of uterine lesions seemed increased in HJT, especially with concern to leiomyomas, adenofibromas, and adenomyosis. The underlying pathogenic mechanisms and the involvement of CDC73 pathogenic variants and parafibromin expression are yet to be explored. Currently, the heterogeneous expression of parafibromin status and, the wide spectrum of CDC73 mutations including the variety of clinical presentations in HJT, make it difficult to predict the phenotype based on the genotype. The central role of HJT-PHP is, however, the main clinical element, while the elevated risk of parathyroid carcinoma requires a special awareness.

HPV related p16INK4A and HSV in benign and potentially malignant oral mucosa pathologies.

BACKGROUND: The association of Human Papilloma Virus (HPV) and Human Syncytial Virus (HSV) infection with inflammatory and potentially malignant disorders of the oral cavity (OPMD) is unknown. The aim of this cross-sectional study was to stablish the expression of the p16INK4A and HSV proteins, to test potential correlation between those parameters in biopsies from clinically diagnosed oral lesions. METHODS: Immunochemical analysis of 211 formalin-fixed, paraffin-embedded (FFPE) blocks from 211 individuals was provided. The clinical diagnosis included in the research were Oral lichen planus (N = 30), Oral Leukoplakia (N = 13) Mucocele (N = 25), Erosion/ulceration/ inflammation of mucosa (N = 8), Overgrowth of mucosa (N = 135). RESULTS: Two hundred eleven analyzed FFPE samples resulted with the median age of 58.5 years (the average age 54.0 years and SD ± 17 years). The female/male ratio was 2.3 (69.7% vs 30.3% respectively). All the samples positive for HSV also expressed p16INK4A (p = 0.000), that's showed various levels of association with the diverse clinical diagnosis reaching the higher level in OM 49.1% (29 positive samples) and OLP 30.5% (18). p16INK4A was associated with OLP at 30.5% (18), and fibroma 30.5%. HSV expression was mostly present in fibroma at 47.6% (10 positive samples). CONCLUSION: HSV and p16INK4A positivity in relation to diagnosis of the biopsies showed statistically most often p16INK4A in OLP and fibroma. The results of co-expression of p16INK4A and HSV in mucocele and fibroma in oral mucosa suggest a cooperation between the molecular alterations induced by these two viruses. Squamous papilloma samples positive for p16INK4A were also positive for HSV, suggesting that the putative pro-oncogenic action of HSV could be an early event.