BDS10015 Benign Neoplasms ngu.pdf

BDS10015 The histopathology of some benign soft tissue lesions of the oral mucosa Aims: The aim of this lecture is to detail the histopathological features of some benign soft tissue lesions of the oral mucosa Objectives: On completion of this lecture, the student should be able to: • Understand t...

BDS10015 The histopathology of some benign soft tissue lesions of the oral mucosa Aims: The aim of this lecture is to detail the histopathological features of some benign soft tissue lesions of the oral mucosa Objectives: On completion of this lecture, the student should be able to: • Understand the histopathology of lymphangioma, haemangioma and lipoma • Understand the histopathology of genodermatoses and it’s role in the diagnostic process • Understand the histopathology of local reactive lesions. Benign neoplasms are classified according to tissue of origin Epithelial Benign Epithelial Neoplasms 1. Squamous cell papilloma 2. Keratoacanthoma Mesenchymal ➢Keratoacanthoma Definition: It is a self limiting - benign epithelial tumor that resembles well differentiated squamous cell carcinoma, clinically and histologically. Etiology: Unknown etiology but may be due to: 1. genetic or viral factors (HPV 26, 37) 2. Actinic radiation (frequent occurrence on sun exposed surfaces of the skin) Keratoacanthoma Clinical Picture ▪ Asymptomatic, ▪ Occurs in old age, males > females ▪ Common site: outer edge of the vermillion border of lips (sun exposed areas of the skin), rare intraorally. ➢Keratoacanthoma Clinical Picture ▪ It appears as a sessile, firm, well demarcated nodule with a central depression filled with keratin (central plug of keratin), yellowish or brown [Intraoral keratoacanthoma usually lack the central plug]. ▪ It passes through 3 phases ➢Growth phase [rapid enlargement to its full size 1-2 cm over 6 weeks] ➢Stationary phase [persists as a static lesion for another 6 weeks] ➢Involution phase [spontaneous regression by expulsion of its keratin core & heals with scar tissue] ➢Keratoacanthoma Clinical Picture Spontaneous regression of keratoacanthoma ➢Keratoacanthoma Keratin ➢Keratoacanthoma Histopathology Epithelium 1. Show hyperkeratosis with a crater filled with keratin 2. At base of crater: hyperplastic epith. growing into underlying C.T 3. Show dyskeratosis (abnormal keratosis) 4. Normal epith. at edge of the lesion Connective tissue Infiltrated with chronic inflammatory cells ➢Keratoacanthoma ❖Biopsy should include adjacent clinically normal epithelium ❖Involucrin (a marker for terminal keratinocyte differentiation) indicates complete terminal differentiation in keratoacanthoma rather than squamous cell carcinoma Benign Neoplasms of Mesenchymal Origin Neural lesions 1. Fibroma 2. Lipoma 3. Myomas 1.Granular cell tumor 2. Schwanoma 3. Neurofibroma 4. Melanotic n. tumor of infancy Non odontogenic tumors of the jaw 1. chondroma 2. osteoma ➢Fibroma Definition: It is a benign neoplasm of fibrous C.T. ❖ the most common tumor of the oral cavity is believed to be reactive hyperplasia of fibrous C.T. rather than a true neoplasm ❖That’s why, it was omitted by WHO (5th edition) from classification of benign neoplasms ➢Lipoma Definition: It is a benign neoplasm of fat, which is rare intraorally Clinical Picture ▪ Slowly growing, asymptomatic, soft swelling ▪ show smooth surface of sometimes yellowish ➢Lipoma Histopathology ▪The lesion is capsulated ▪It is formed of mature fat cells which appear as polyhedral cells with clear cytoplasm, their nuclei are compressed against one side of the cell membrane (signet ring appearance) ➢Granular cell tumor* Definition: A benign neoplasm of Schwann cell differentiation characterized by accumulations of plump granular cells. It shows predilection to the oral cavity. Clinical Picture ▪Slowly growing, sessile mass ▪Asymptomatic, rubbery-firm well defined mass ▪Affects both males & females at middle age ▪The most common site is tongue then buccal mucosa and lip ➢Granular cell tumor* Histopathology ▪It consists of nests or sheets of large polyhedral cells in C.T. stroma ▪The cells show eosinophilic granules in the cytoplasm, which are distributed around central or eccentric small nuclei. ▪The lesion is covered by hyperplastic st. sq. epithelium with atypical proliferation referred to as pseudoepitheliomatous (pseudocarcinomatous) hyperplasia ➢Granular cell tumor* Differential Diagnosis ▪ Congenital epulis of new born a rare benign tumor that affects the alveolar process of newborns and is composed of sheets and nests of cells with abundant granular cytoplasm ➢Schwanoma Definition: Benign neoplasm of nerve tissue origin arising from Schwann cells. Clinical picture • It may be solitary, Bilateral [Neurofibromatosis type2] or Multiple [schwanomatosis] ▪ It is slow growing mass, usually asymptomatic , but pain may occur in some instances ▪ Intraorally, it can occur anywhere, however, tongue is the most common site ➢Schwanoma Histopathology Antoni type A Antoni type B ➢Schwanoma Histopathology It is composed of spindle cells that are arranged in two microscopic patterns Antoni type A •The tissue is compact and solid •A characteristic feature is the palisading arrangement of cells and their nuclei in rows (known as nuclear rows of Verocay) around acellular eosinophilic areas (known as Verocay bodies). Antoni type B •Loosely textured •Cells and fibers are haphazardly arranged ➢Neurofibroma Definition: It is a benign neoplasm of peripheral nerve tissue, which arises from a mixture of Schwann cells & perineural fibroblasts (the most common type). Clinical picture • • ▪ Neurofibroma exists in two forms: Solitary or Multiple [Neurofibromatosis type 1] It is slow growing mass, usually asymptomatic Intraorally, tongue and buccal mucosa are the most common sites Neurofibromatosis (Von Recklinghausen disease of skin) •It is inherited as an autosomal dominant trait •The gene responsible for neurofibromatosis type I is NF1 which is mapped to chromosome 17 •It appears as multiple sessile nodules •areas of melanin pigments known as “café au lait” spots ➢Neurofibroma Histopathology The tumor is composed of interlacing bundles of spindle shaped cells with wavy nuclei in delicate C.T. ❖The most feared complication is development of cancer (neurofibrosarcoma or malignant schwannoma) ➢Melanotic neuroectodermal tumor of infancy Definition: It is a locally aggressive pigmented neoplasm that usually occurs during the 1st year of life. It is of neural crest origin. Clinical picture ▪ Striking predilection for the maxilla, especially the anterior area. ▪ Rapidly expanding blue or black mass. ▪ It often destroys the underlying bone, causing displacement of developing teeth. ➢Melanotic neuroectodermal tumor of infancy ▪Lab findings: High levels. of urinary vanillylmandelic acid [these levels return to normal once the tumor is resected Histopathology The tumor consists of biphasic population of cells that form nests, cords in connective tissue stroma. The cells are: Large melanin producing epithelioid cells Small round neuroblast like cells Benign Neoplasms of Mesenchymal Origin Neural lesions 1. Fibroma 2. Lipoma 3. Myomas 1.Granular cell tumor 2. Schwanoma 3. Neurofibroma 4. Melanotic n. tumor of infancy Non odontogenic tumors of the jaw 1. chondroma 2. osteoma ➢Chondroma Definition: It is a benign neoplasm of mature hyaline cartilage. Although it’s very rare in oral cavity, many of the reported cases have recurred and exhibited malignant behavior. ❖It is wise to consider chondroma of the jaw as a potential chondrosarcoma because the microscopic distinction between benign chondroma and low-grade chondrosarcoma of the jaw is difficult. ❖That’s why, it was omitted by WHO (5th edition) from classification of benign neoplasms Osteoma* Definition: It is a benign neoplasm of mature bone, which is restricted to the craniofacial skeleton, and rare in other bones Clinical picture ▪ It appears as slowly growing hard swelling ▪ Asympotomatic, occurs at any age (10-70) ▪ Osteoma may be either solitary or multiple [associated with Gardner’s syndrome] Osteoma* Clinical picture Osteoma may be either: surface or peripheral which arise on the surface of bone causing facial deformity central osteoma which arise in the medullary bone. Small lesions are asymptomatic but large lesions cause slowly progressive enlargement of the affected area Osteoma* Radiographic features Well circumscribed radioopaque mass Gardner’s syndrome Osteoma* Histopathology It is formed of dense compact or cancellous bone, or combination of both. Gardner’s syndrome It is characterized by variable abnormalities in bone, skin and teeth as well as colorectal polyps Multiple Fibromas & osteomas Multiple impacted Supernumerary teeth Multiple polyps in large intestine (premalignant) ❖The major problem for these patients is high risk for transformation of colorectal polyps into adenocarcinoma if untreated. Multiple osteomas are noted around puberty, leading to early diagnosis Hamartoma Developmental malformation presents as tumor-like condition, characterized by presence of normal tissue in normal site but in exaggerating manner ➢Haemangioma Definition: It is a benign vascular hamartoma affecting the mucosa. It is considered as a tumor of infancy that shows rapid growth, followed by gradual involution. ➢Haemangioma Clinical picture ▪ These are common lesions in the head and neck that occur slightly after birth or during early childhood ▪ It may be solitary or multiple, central (intraosseus) or peripheral ▪ It appears as red (strawberry haemangioma) or reddish purple lesions ▪ It is flat or slightly elevated with smooth surface ▪ Tongue is most common intraoral site ➢Haemangioma Histopathology Capillary It consists of small blood spaces lined by endothelial cells that are separated by C.T. stroma Cavernous It consists of large blood spaces that may show papillary enfolding and lined by endothelial cells The spaces are separated by C.T. stroma ➢Haemangioma ❖ Unlike haemangiomas, vascular malformations are present at birth and persist throughout life. Sturge-Weber disease ▪ Vascular malformation of the skin (port wine stain or nevus flammeus) has a unilateral distribution along the trigeminal nerve ▪ Ocular involvement as (glucoma, exophthalmus and hemangioma of choriods) ▪ Neurologic manifestations as convulsions which often results in mental retardation or hemiplegia ➢Lymphangioma It is a benign hamartomatus tumorlike growth of lymphatic vessels. It has marked predilection to the head & neck. Clinical picture •The most common site intraorally is anterior 2/3 of the tongue •It may be either Superficial lesion It demonstrates a pebbly surface (frog eggs) of same color or slightly redder than normal mucosa Deep diffused lesion It shows no change in surface texture or color of mucosa involved. It causes macroglossia if tongue is affected ➢Lymphangioma Histopathology It consists of many endothelial lined spaces that are either empty or contain lymphoid material and occasional blood cells. Lymphoid aggregates in walls of vessels are seen. Benign neoplasms Epithelial neoplasms Squamous cell papilloma Mesenchymal neoplasms Fibroma, lipoma, myxoma, myoma Hamartomas haemangioma Neural Non keratoacanthoma odontogenic tumors of the jaw lymphangioma Key points ▪ Benign epithelial neoplasms include: squamous cell papilloma [discussed before with papillomas] and keratoacanthoma [may be mistaken for squamous cell carcinoma] ▪ Benign mesenchymal neoplasms [in soft tissue] include: fibroma, lipoma, myxoma, myoma and neoplasms of neural origin ▪ Melanotic neuroectodermal tumor of infancy and myxoma are locally aggressive benign neoplasms ▪ Benign mesenchymal neoplasms [occur in jaw bone] include: osteoma and chondroma [non odontogenic jaw tumors] ▪ It is wise to consider chondroma of the jaw as a potential chondrosarcoma because the microscopic distinction between benign chondroma and low grade chondrosarcoma of the jaw is difficult ▪ Hamartoma is a developmental malformation presents as tumorlike condition, it includes hemangioma and lymphangioma Aims: The aim of this lecture is to detail the histopathological features of some benign soft tissue lesions of the oral mucosa Objectives: On completion of this lecture, the student should be able to: • Understand the histopathology of lymphangioma, haemangioma and lipoma • Understand the histopathology of genodermatoses and it’s role in the diagnostic process • Understand the histopathology of local reactive lesions. Reading material: Students are advised to review any relevant teaching provided in the first year. In addition they are advised to read relevant sections of the following texts: •Robinson M et al. Soames’ and Southam’s Oral Pathology. 5th edition. Oxford University Press, 2018 pp 15-25 •Odell E.W. Cawson’s Essentials of Oral Pathology and Oral Medicine. 9th Edition. Elsevier, 2017 pp 369-376 Thank you