Discussion
Langerhans cell histiocytosis, formerly known as histiocytosis X, is a
term used to describe a group of clinico-pathological conditions marked
by a monoclonal proliferation of histiocyte-like cells followed by
varying numbers of eosinophils, lymphocytes, plasma cells, and
multinucleate giant cells on histological
examination.5 The histiocytes present here is
recognised as Langerhans cells. Langerhans cells are dendritic
mononuclear cells which are generally found in the epidermis, mucosa,
lymph nodes, and bone marrow. They generally present antigens to
T-lymphocytes; however literature review of LCH indicates that
Langerhans cells proliferate monoclonally, resulting in the destruction
of hard and soft tissues.6 Despite significant
progress in medical fields, the pathophysiology of LCH remains unclear;
suggested mechanisms are the product of either an abnormal autoimmune
response or a neoplastic process.4
LCH can affect people of wide age range, but it is more common in
children under the age of 15 years, with a peak occurrence at 2–4 years
and a male predilection that is twice as high as that of
females.2 The present case was reported in a
five-year-old male child. The jaws are involved twice as commonly as the
oral soft tissues. The mandible is three times more frequently affected
than the maxilla with a higher predisposition for the posterior regions
of the jaws than the anterior regions.7 These findings
are similar to the present case where mandibular posterior regions were
affected more. In about 5%-75% of patients, oral manifestations are
the first signs and symptoms and sometimes the only symptom of LCH,
thus, prompting the patient to seek treatment from a
dentist.8 Eden P et al., reported in a case series
(n=13) that seven of the cases showed intra-osseous lesion in the
posterior region of the jaw and oral mucosal involvement (tongue, buccal
mucosa and gingiva).9 Sore throat, halitosis,
gingivitis, gingival hypertrophy, unpleasant taste, tooth mobility with
alveolar expansion, jaw pain, facial swelling, mental nerve anaesthesia,
and inability of extracted tooth sockets to heal are some of the oral
symptoms. The loss of supporting alveolar bone may be mistaken for
advanced periodontitis.8 In the present case, palatal
ulcer, tooth mobility, pain, and bone loss were the features in
consideration.
According to Krooks et al., the involvement of nails is uncommon, but
can be seen as subungual pustules, hemorrhage, purpuric striae, purulent
discharge, longitudinal grooving, onycholysis, paronychia, and
pitting.4 In the present case as well, changes in the
nails were evident. LCH lacks the pathognomonic clinical or radiographic
features, thus, a definite diagnosis is based on a histologic and
immune-histochemical examination, where CD1a, Langerin (CD207), and
S-100 protein positivity is common.10 S-100 is a
calcium binding protein present in the nucleus and cytoplasm of glial
and schwann cells, melanocytes, chondrocytes, adipocytes and
myoepithelial cells and is positive for all tumors derived from these
cells. CD1a is expressed on Langerhans precursors, Langerhans cells and
thymic cortical T cells, whereas Langerin is a type II transmembrane
cell surface receptor produced by Langerhans cells which helps in
differentiating Langerhans cell histiocytosis from other non-Langerhans
cell histiocytic proliferations. As in our case immunostaining was
positive for CD1a, Langerin, and S-100, it helped in confirming the
diagnosis of LCH.
The dentists are usually the first clinicians to examine the child’s
oral cavity, hence, awareness regarding the varied manifestations of
this rare condition is important for early diagnosis and appropriate
referral of the patient. Also, multidisciplinary approach is necessary
for the overall management and well-being of the child. Since, the
lesions present in LCH may be confounded with a malignant process,
histological and immune-histochemical tests play a vital role in
confirming the diagnosis.3
Conclusion
Langerhans cell histiocytosis is a disease with a wide range of clinical
symptoms. LCH, being a rare condition, is at a high risk of being
misdiagnosed or underdiagnosed. A thorough history, clinical
examination, appropriate investigations and a sound knowledge of the
condition helps to make a correct diagnosis at an early stage, thus
reducing the morbidity and mortality associated with this pathology. An
interdisciplinary approach is also imperative for the success of the
management of the condition.