Hamartomas

Fig. 23.1
Light microscopy of neuroglial hamartoma. a Mature neuroglial tissue with ribbons of ganglionic elements. b Immunohistochemically, ganglion cells with neuritic and axonal processes are strongly immunoreactive for S100 protein. c Nerve structure surrounded by concentrically arranged perineurial cells. d Neuroglial component immunoreactive for glial fibrillary acidic protein (GFAP)
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Fig. 23.2
Light microscopy of external ear canal hamartoma. Cartilaginous nodule partially covered by attenuated squamous epithelium
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Fig. 23.3
Light microscopy of middle ear hamartoma. Connective tissue with sebaceous glands (arrows) and bundles of smooth muscle (clefted arrowheads) is covered by respiratory type ciliated epithelium (asterisks) and foci of mucous cells (arrowheads)
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Fig. 23.4
Light microscopy of dermal hamartoma. Abnormal dermal tissue with enlarged erectory pili (arrows), thick bands of smooth muscle (arrowheads) and disorganized adnexa
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Fig. 23.5
Fibrous hamartoma of infancy. The lesion is composed of a mixture of mature adipose tissue, fibrocollagenous bands and islands of primitive mesenchyme (arrows). Fibrous hamartoma of infancy of the head and neck is usually located in the scalp

Biology and Epidemiology

Pathophysiology

  • The clinical presentation of hamartomas will depend upon the area of involvement.
  • Hypothalamic hamartomas (HH) are associated with seizure activity and/or central precocious puberty (CPP) .
    • Estimated that 14–58 % of CPP cases are caused by HH; HHs are the most common cause of CPP [2].
    • Gelastic seizures are common and notoriously intractable.
      • The hypothalamic hamartoma is intrinsically epileptogenic.

Molecular/Genetic Pathology

  • A molecular pathway to hamartoma formation can be seen in the disorder tuberous sclerosis, in which subependymal giant cell astrocytomas form [3]:
    • Caused by mutation in either of two tumor suppressor genes, TSC1 or TSC2.
    • The products may be involved in the inhibition of tumor formation.
      • Hamartin may regulate cellular adhesion by ezrin-radixin-moiesin family proteins and the GTP-binding protein Rho [4].
      • Tuberin may inhibit the G1/S transition and promote entry to the G0 phase by inhibiting rap1 or other small GTP-binding proteins [5].
  • The inheritance pattern of hamartomas is dependent upon the specific tumor and area of involvement.
    • Tuberous sclerosis is autosomal dominantly inherited [3].
    • Nasal chondromesenchymal hamartomas (NCMH) may have a genetic basis with partial penetrance dependent upon environment [6].

Incidence and Prevalence

  • Pediatric hamartomas are rare .
    • Fewer than 15 cases of lingual hamartomas exist in the literature [7].
    • Eleven reported cases of laryngeal hamartomas [8].
    • Two reported cases of pediatric tracheal hamartomas [9].
    • Three reported cases in the middle ear [10].
  • Hamartomas are the second most common benign pediatric pulmonary tumor of the lung, though bronchial tumors in general are rare [11].

Age Distribution

  • Laryngeal hamartomas manifest most commonly in children younger than 10 years of age, or adults in their sixth decade of life [1].
  • Nasal chondromesenchymal hamartoma occurs most often in those younger than 1 year of age [6].

Sex Predilection

  • Two-thirds of laryngeal hamartoma patients are male [1].
  • Male infants are more commonly affected in nasal chondromesenchymal hamartoma [6].
  • Fibrous hamartoma of infancy also occurs primarily in male patients [12].

Relationships to Other Disease States, Syndromes

  • Tuberous sclerosis may be associated with West Syndrome [3] .

Presentation

Presentation depends on area of involvement:
Laryngeal hamartoma [1, 8]:
  • Stridor
  • Dysphagia
  • Dysphonia
  • Dyspnea
  • Earache
  • Aspiration
Nasal [13] or nasal chondromesenchymal hamartoma (NCMH) [6, 14]:
  • Nasal obstruction
  • Respiratory and feeding difficulties in infants
  • Epistaxis
  • Rhinorrhea
  • Serous otitis media
  • If orbital involvement: proptosis, enophthalmos, ophthalmoplegia, ptosis, or hypotropia
  • If intracranial expansion: hydrocephalus or with oculomotor disturbances
Figure 23.6 shows a gross example of a nasal mass.
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Fig. 23.6
An anterior, polypoid tongue mass that proved to be a hamartoma upon histological examination. (Reprinted from Horn et al. [8], with permission of SAGE Publications)
Tongue lesions [7]:
  • Airway obstruction
  • Oral bleeding
  • Cosmetic concern
  • Dysphagia
  • Dysarthria
  • Respiratory distress, especially if in posterior tongue
Figure 23.7 shows a gross example of a tongue lesion.
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Fig. 23.7
A gross image of a nasal hamartoma that filled the right nasal meatus of a child, with the computed tomography (CT) scan revealing the right nasal mass adjacent to the nasal septum. (Reprinted from Gajda et al. [13])
Tracheal [9]:
  • Similar to intractable asthma or obstructive airway disease
  • Expiratory wheezing
  • Biphasic stridor
Fibrous hamartoma of infancy (FHI) [12, 15, 16]:
  • Solitary mobile and firm mass, gradually enlarging
    • Most are 2.5–5 cm in diameter
  • Can occur on neck
  • Occasional skin change, such as pigmentation changes or eccrine gland hyperplasia
Hypothalamic hamartomas [17, 18]:
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Dec 28, 2016 | Posted by in PEDIATRICS | Comments Off on Hamartomas

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