Multisystem Langerhans cell histiocytosis with diabetes insipidus in an adult.

Sir,

A 46-year-old male patient presented with craniofacial papule desquamation for more than seven years and perianal erosion for more than one year. He had a history of pituitary adenomas and central diabetes insipidus which was treated with desmopressin acetate. The perianal lesions were cauliflower at first. After treatment in local hospital, local rupture appeared after electrocautery and the area of skin erosion gradually expanded. Physical examination revealed diffuse multiple papular pustules and greasy scabs on the head and face, perianal erosion, flushing of the skin base and obvious local secretions [Figure 1]. Pathological biopsy of lip and perianal skin showed round cell tumor with a large number of histiocytes with very little eosinophil infiltration [Figure 2a, b]. The results of skin immunohistochemistry showed tumor cells CD1a (3 +), S100 (3 +), CD207 (3 +), CD68 (+), CKpan (-), CK7 (-), p63 (-), HMB-45 (-), Melan-A (-), CD117 (-), Ki-67 (about 20%) [Figure 2c, d].

Figure 1

LCH presenting as diffuse multiple papular pustules and greasy scabs on the head and face (a, b), perianal erosion (c)

Figure 2

Langerhans cells with abundant eosinophils are observed (40 × 10) (a, b) Langerhans cells show immunopositivity for CD1a (c) and S-100 (d)

No obvious abnormalities were found in blood routine, blood biochemical, urine routine, autoantibodies, humoral immunity, infectious diseases, computed tomography (CT) of the chest, and abdominal color doppler ultrasound. The results of brain magnetic resonance imaging (MRI) enhancement hinted that the lesions of mesencephalon and pons may be large considering inflammatory demyelination, and cavernous hemangioma of right frontal cortex can also be seen [Figure 3]. Full-body bone scan by Emission Computed Tomography (ECT) (ECT) revealed multiple abnormal concentration foci (right temporal bone, left iliac bone, bilateral lower femur, bilateral upper and lower tibia, right foot bone, etc.) [Figure 4]. Bone marrow puncture cytological examination: 1. The results of bone marrow biopsy of the left anterior superior iliac spine showed that bone marrow hyperplasia was active with scattered plasma cell infiltration; 2. Immunohistochemistry: CD43 (2+); CD20(-), CD3(-), CD138(loose +); CD38(dispersion +); CD1a(-); Langerin(-), Ki67 about 1%. BRAFV600E/D gene mutation was negative.

Figure 3

Brain MRI enhancement hints: For mesencephalic and pontine lesions, inflammatory demyelinating lesions are more likely to be considered

Figure 4

Full-body bone scan by ECT revealed multiple abnormal concentration foci

Thus, we diagnosed multisystem Langerhans cell histiocytosis (LCH) with diabetes insipidus.[1] The patient was treated with dexamethasone, cytarabine, and methotrexate. After six months of follow-up, the patient's skin lesions subsided and his condition was stable [Figure 5].

Figure 5

Head and face rash subsided (a), and pigmentation remained around the anus(b)

LCH is a rare inflammatory myeloid tumor characterized by abnormal clonal proliferation of CD1a+/CD207+ dendritic cells.[1] The incidence of LCH is 1 to 2 cases per million in adults. In adults, the most common organs affected by LCH are bone (80%), skin (33%) and pituitary gland (25%). Other affected organs include spleen, hematopoietic system, lungs (15% each); lymph nodes (5-10%); and central nervous system excluding pituitary gland (2-4%).[2] BRAFV600E mutations have been found in over 50% of LCH cases, and this gene increases the risk of recurrence after LCH treatment.[3] However, we did not find BRAFV600D/E gene mutations in this case.

In addition, our patient had metatarsal involvement, which is very rare. To our knowledge, this is the second reported case of metatarsal invasion in adults. Because LCH involving the hand foot tube is extremely rare, it needs to be differentiated from the mimicry of other diseases. These diseases include osteomyelitis (such as bacterial, fungal, tuberculous); malignant bone tumors (such as Ewing's sarcoma, lymphoma, leukemia); benign bone tumor (such as a simple bone cyst, osteoid osteoma, aneurysmal bone cyst, giant cell tumors); and foreign bodies–induced lesions (such as glass, a thorn, pieces of wood, rubber, etc.).[4]

Skin is one of the most common sites involved in adult LCH, but the patient we reported presented with perianal involvement, which is rare. Abdou et al.[5] summarized 16 cases of LCH with perianal lesions from 1984 to 2016. The perianal clinical manifestations are similar to condyloma acuminatum. Lymphoma, signet ring carcinoma, and melanoma should be considered in the differential diagnosis under the microscope. Biopsies and the exclusion of immunohistochemical markers are required. The possibility of LCH should be considered in patients like ours where local treatment fails.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.