Neoplasms of the Ear and Temporal Bone

Clinical

• No gender predilection; most frequently seen in the sixth to seventh decades of life

• Frequently develop on sun-exposed skin:

  • Majority occur on the face (most commonly on the cheek and nose)

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      Approximately 10% occur on the external ear (pinna); occasionally may occur on the lips

• Usually a solitary lesion but multiple KAs occur

• Initially the lesion appears as an erythematous papule or may resemble a wart but over a 1- to 2-month period undergoes rapid enlargement to appear as an exophytic or dome-shaped nodule with a central keratin crater measuring from 1 to 3 cm in diameter.

• Typically arise rapidly (6 to 8 weeks) followed by a stationary period lasting up to several months which in turn is followed by involution with spontaneous regression ultimately leading to (crateriform) scar.

• Whole growth process may be seen over periods of several months up to a year.

• Etiology is unknown but is probably the result of actinic damage.

• Multiple and syndromic keratoacanthomas exist and may occur in patients with genetic predispo­sition.

• Less common variants include:

  • Giant keratoacanthoma:

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      Grows rapidly and reaches a size of 5 cm or more

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      May cause destruction of underlying tissues

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      Spontaneous involution occurs after several months.

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      Most common sites are the nose and eyelids.

  • Keratoacanthoma centrifugum marginatum:

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      May reach 20 cm in diameter

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      No tendency to spontaneous involution

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      Peripheral extension with raised, rolled border and central atrophy

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      Most common sites are dorsa of hands and legs

  • Subungual keratoacanthoma:

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      Aggressive behavior that fails to regress spontaneously

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      Destructive growth in distal portion under a fingernail

• Described as part of Muir-Torre syndrome, which is characterized by:

  • Multiple neoplasms of the skin, including those with sebaceous differentiation and internal (visceral) neoplasms, the most common of which are of colonic origin (adenocarcinoma, adenoma)

  • In Muir-Torre syndrome, KAs may be one of mul­tiple cutaneous lesions or represent the only type of cutaneous tumor present in this syndrome.

Pathology

Differential Diagnosis

• Benign keratosis

• Seborrheic keratosis, including inverted follicular keratoma

• Squamous cell carcinoma:

  • Differentiation from squamous cell carcinoma is made on the basis of the overall architecture because cytologic atypia is not a reliable criterion for differentiating KA from squamous cell carcinoma.

  • Differentiation can be extremely difficult especially if less than adequate biopsy material is provided (e.g., from the central aspects of the tumor).

  • No reliable immunohistochemical staining and/or molecular biologic analyses allowing for differentiating KA from squamous cell carcinoma

Treatment and Prognosis

• Complete surgical excision is the preferred treatment and is curative.

• Despite the result of involution and regression, keratoacanthomas should be treated surgically for the following reasons:

  • Cosmetic considerations

  • Allow for the best overall architectural evaluation to confirm the diagnosis and help differentiate from a squamous cell carcinoma

  • Treatment would be the same for a well-differentiated squamous cell carcinoma in this location.

  • A small percentage of cases may recur.

• Keratoacanthomas have been reported to metastasize; however, the metastases have been squamous cell carcinomas, suggesting that the primary tumors may have also been squamous cell carcinomas.

• Presence of vascular and/or perineural invasion are not findings indicative of malignancy.

• Diagnosis of KA as opposed to squamous cell carcinoma can be made if certain conditions are met, including:

  • Clear-cut clinical description of the lesion is provided.

  • Clinical history of rapid evolving lesion with KA as the primary clinical diagnosis

  • No history of immunosuppression

  • Adequate biopsy provided allowing for complete visualization of the lesion

  • Classic histologic findings are identified.

  • In the absence of these conditions a diagnosis of squamous cell carcinoma is likely.

Clinical

• Affect men more often than women; over a wide age range but is most frequently seen in the fifth to sixth decades of life

• Symptoms include a slow-growing external auditory canal mass or blockage, hearing difficulty, and infrequently, otic discharge.

Pathology

Differential Diagnosis

• Pleomorphic adenoma of ceruminal or parotid gland origin

• Middle ear adenoma:

  • May perforate the tympanic membrane and appear to present as an external auditory canal mass, creating potential difficulty in differentiation from a ceruminal gland adenoma

  • Histologic features of both tumor types should allow for relatively easy differentiation from one another.

• Ceruminal gland adenocarcinoma

Treatment and Prognosis

• Complete surgical excision is the preferred treatment and is curative.

• Recurrence of the tumor can occur and relates to inadequate surgical excision.

Clinical

• No gender predilection; most frequently occurs in the third through fifth decades of life

• Subcutaneous proliferation with a predilection for the external ear (auricle and external canal), as well as other head and neck sites, including the scalp and forehead ( Fig. 24-8 )

• Symptoms include pruritus and bleeding following scratching; regional lymphadenopathy and peripheral eosinophilia are uncommon but may be present.

• History of trauma elicited in a number of cases, as well as the microscopic impression of vascular damage, and the demonstration of immunoglobulin deposits in the vessels have led several observers to favor a reactive or reparative etiology.

• Hormonal influences may play a role in some cases, as suggested by the association with pregnancy in some patients and by the age and gender distribution of the disease.

• Human herpesvirus 8 (HHV-8) has not been identified in association with EH.

Pathologic Features

Differential Diagnosis

• Lobular capillary hemangioma:

  • Prominence of epithelioid endothelial features and associated lymphoplasmacytic and eosinophilic infiltrate contrast with findings in hemangiomas.

• Infantile hemangioma:

  • GLUT1 positive

• Angiosarcoma:

  • Shows a diffusely infiltrative lesion composed of anastomosing vascular channels lined by pleomorphic cells with increased mitotic activity

  • Presence of the characteristic inflammatory infiltrate in EH typically not found in angiosarcoma

Treatment and Prognosis

• Local surgical excision or desiccation are the preferred treatments and are curative:

  • Rarely, lesions may regress.

• Recurrence reported in up to one-third of cases

• Metastasis virtually never occurs.

• Superficial radiotherapy results in at least partial response in the majority of patients.

• Intralesional or systemic steroids, cryotherapy, and intralesional vincristine, bleomycin, and fluorouracil not proven to be curative

Clinical

• Not considered synonymous with EH

• Occurs in subcutis of the head and neck; other less common sites of involvement include groin, extremities, and chest wall

• In contrast to EH:

  • Occurs primarily in Asians and tends to affect males

  • Often associated with regional lymphadenopathy and peripheral eosinophilia

  • Increased serum immunoglobulin E (IgE), proteinuria, and nephrotic syndrome may occur as part of the disease.

  • Tend to be larger lesions that are predominantly subcutaneous nodules with a tendency to occur in locations other than in the head and neck

• Etiology is unknown:

  • Presence of peripheral eosinophilic and elevated serum IgE suggests immunologic reaction to an unknown stimulus.

Pathology

Differential Diagnosis

• Lobular capillary hemangioma

• Angiosarcoma

Treatment and Prognosis

• Local surgical excision or desiccation are the preferred treatments and are curative.

• Recurrence occasionally occurs.

• Malignant transformation or association with malignancy not reported

Treatment and Prognosis

• Surgery is curative.

Differential Diagnosis

• Myxoid neoplasms:

  • Myxoid change occurs in a variety of benign neoplasms, including neurofibroma, neurilemmoma, and lipoma, may mimic myxoma, especially in limited biopsy material.

  • Of greater concern is that the histologic pattern in myxomas may mimic myxoid soft tissue malignancies, which are much more common in this location, particularly embryonal rhabdomyosarcoma, and less commonly undifferentiated pleomorphic sarcoma, low-grade fibromyxoid sarcoma, myxoid liposarcoma, and myxoid chondrosarcoma.

  • In contrast to myxoma, sarcomas display:

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      Much greater cellularity

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      A richer vascular pattern often with delicate plexiform capillary vascular network

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      Differing cytologic features including cellular pleomorphism with increased mitotic figures; multinucleated giant cells in undifferentiated pleomorphic sarcoma; cytoplasmic MUC4 in low-grade fibromyxoid sarcoma; lipoblasts in liposarcoma; rhabdomyoblasts in rhabdomyosarcoma; and atypical chondroblasts in chondrosarcoma are distinctive features for these sarcoma types.

Treatment and Prognosis

• Surgery is the preferred treatment.

• Although soft tissue myxomas lack a discrete capsule, they rarely recur after excision.

Clinical

• Generally considered an uncommon neoplasm

• No gender predilection; occurs over a wide age range but is most common in the third to fifth decades of life

• Any portion of the middle ear may be affected, including the eustachian tube, mastoid air spaces, ossicles, and chorda tympani nerve.

• Most common symptom is that of unilateral conductive hearing loss:

  • Fullness, tinnitus, and dizziness may also occur.

  • Pain, otic discharge, and facial nerve paralysis rarely occur and may be indicative of a malignant process.

• Otoscopic examination in the majority of cases will identify an intact tympanic membrane with tumor confined to the middle ear space with possible extension to the mastoid; occasionally, the adenoma will perforate through the tympanic membrane with extension into and presentation as an external auditory canal mass.

• No known etiologic factors related to the development of MEA:

  • Not associated with a prior history of chronic otitis media

  • Concurrent cholesteatomas may be seen but there is no known association between these two lesions.

• Radiologic imaging:

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      In its more typical radiologic presentation, appears as a relatively avascular soft tissue density without evidence of destructive, invasive, or erosive properties.