Translate this page into:
A novel case of adult xanthogranuloma mimicking keratoacanthoma
Corresponding author: Dr. Shuaihantian Luo, Department of Dermatology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China. lsht5309@csu.edu.cn
-
Received: ,
Accepted: ,
How to cite this article: Long X, Zhang G, Luo S. A novel case of adult xanthogranuloma mimicking keratoacanthoma. Indian J Dermatol Venereol Leprol. doi: 10.25259/IJDVL_1122_2025
Dear Editor,
Xanthogranuloma (XG) is a benign proliferative disorder of histiocytic origin, primarily classified under non-Langerhans cell histiocytosis (non-LCH). While juvenile xanthogranuloma (JXG) is commonly observed in early childhood, adult-onset XG is rare, accounting for approximately 10% of all cases. Here, we present a novel case of adult XG clinically mimicking keratoacanthoma (KA).
A 20-year-old female with no significant personal or family medical history presented with a firm, well-demarcated, erythematous, crateriform nodule in the left temporal region. The lesion persisted for 2 months without pruritus or pain. There was no history of trauma. Physical examination revealed a 1.5 × 1.5 × 0.5 cm nodule with focal ulceration and a keratotic plug in the left temporal region. A red halo and pigmentation can be seen around the lesion [Figure 1]. Ophthalmologic, cardiopulmonary, and neurologic examinations were unremarkable. It was initially diagnosed as KA based on clinical features, and immediate surgical resection was recommended. The lesion was completely excised, and histopathological examination revealed a nodular dermal proliferation of xanthomised histiocytes [Figure 2a]. Abundant multinucleated giant cells, including Touton-type giant cells, were seen. A mixed inflammatory infiltrate, predominantly composed of eosinophils and lymphocytes, was also observed [Figure 2b]. Immunohistochemical staining was positive for CD68 [Figure 2c], CD163, and factor XIIIa and negative for S-100 and CD1a. Laboratory investigations showed that complete blood count, triglyceride levels, renal function tests, and serum protein electrophoresis were normal. Based on the history and histopathological results, a diagnosis of adult XG was confirmed. There was no recurrence during follow-up of 1 year.
- The lesion showing erythema, erosion and numerous scabs and scales on the surface.
- Well-circumscribed abnormal epidermal thickening with extensive hyperkeratosis and parakeratosis (Haematoxylin & eosin, 40x).
- Epidermal acantholysis with diffuse atypia of keratinocytes involving the spinous layer and granular layer (Haematoxylin & eosin, 400x).
- The histiocytes staining positive for CD68 (Immunohistochemical stain, 100x).
Adult XG is a rare subtype of non-LCH and represents 10% of all XGs,1 with most cases presenting as solitary, asymptomatic cutaneous nodules on the face.2 It occurs generally between the third and fourth decades of life with equal sex distribution.3 Unlike JXG, which often undergoes spontaneous regression, adult XG tends to persist over time. Pathogenesis remains unclear, although triggers such as infections, trauma, or physical factors have been suggested.4 In this case, the lesion’s crateriform and ulcerated appearance closely mimicked KA, a common clinical differential diagnosis for umbilicated, keratotic nodules.
Histopathologically, XG is characterised by a dense dermal infiltrate of histiocytes, Touton giant cells, and a variable inflammatory component.4 The presence of eosinophils in this case may reflect an immune response to external stimuli or trauma, potentially contributing to the lesion’s clinical appearance. Immunohistochemistry is essential for confirming the diagnosis, with XG typically showing positive staining for CD68, CD163, and factor XIIIa and negative staining for S-100 and CD1a.5 The differential diagnosis for crateriform and keratotic solitary nodules includes KA, squamous cell carcinoma, molluscum contagiosum, solitary reticulohistiocytoma, and prurigo nodularis, while these entities have their unique pathological features [Table 1]. The clinical overlap between XG and KA in the present case highlights the importance of a thorough histopathological and immunohistochemical evaluation.
| Diseases | Clinical features | Histopathological features |
|---|---|---|
| Keratoacanthoma | A dome-shaped nodule with a central keratin-filled crater. Initial rapid growth followed by a period of variable tumour stability and spontaneous regression. | Large squamous cells with hyperchromatic to vesicular nuclei and prominent nucleoli, with abundant, eosinophilic cytoplasm. |
| Squamous cell carcinoma | Enlarging scaly or crusted tender or painful lumps located on sun-exposed sites, particularly the face, lips, ears, hands, forearms, and lower legs. | Squamous epithelial cells nest that emerge from the epidermis layer towards the dermis, atypical cells with eosinophilic cytoplasm with large and vesicular cell nuclei and keratin pearls. |
| Molluscum contagiosum | Single/multiple, round/dome-shaped, pink waxy papule ranging from 1 mm to 5 mm on the face, eyelids, neck, axilla, and thigh. | A crateriform, acanthotic epidermis containing intracytoplasmic molluscum bodies |
| Prurigo nodularis | Pruritic nodules, which usually appear on the arms or legs. | Thick compact orthohyperkeratosis, irregular epidermal hyperplasia, and nonspecific dermal infiltrate containing lymphocytes, macrophages, and eosinophils. |
| Xanthogranuloma | Yellow-reddish to brown dome-shaped papules or nodules in the skin, mucosa or eye. | A dense infiltrate of histiocytes in the superficial dermis and scattered lymphocytes, eosinophils, plasma cells, and Touton cells. |
| Solitary reticulohistiocytoma | Skin-coloured or reddish-brown papules and nodules most commonly occur on the upper half of the body. | A diffuse infiltration of numerous large, mononucleated or multinucleated histiocytes with dense pink cytoplasm referred to as “oncocytic” in the dermis. |
Treatment options for XG include surgical excision, CO2 laser therapy, and intralesional steroids.4 Spontaneous regression was observed in some cases, but systemic involvement and associations with haematological malignancies have been reported in the disseminated type.
In conclusion, we present this novel case with such distinctive features to strengthen awareness regarding the diagnostic challenges posed by adult XG, especially when it mimics other clinically similar entities. Although adult XG typically follows a benign course, awareness regarding its rare presentation and potential associations with systemic conditions is essential for optimal patient management.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for 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.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation
The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.
References
- Juvenile xanthogranuloma: An entity with a wide clinical spectrum. Actas Dermosifiliogr (Engl Ed). 2020;111:725-33.
- [CrossRef] [PubMed] [Google Scholar]
- Revised classification of histiocytoses and neoplasms of the macrophage-dendritic cell lineages. Blood. 2016;127:2672-81.
- [CrossRef] [PubMed] [PubMed Central] [Google Scholar]
- Multiple generalized xanthogranuloma in adult: Case report and treatment. Indian J Dermatol. 2011;56:197-9.
- [CrossRef] [PubMed] [PubMed Central] [Google Scholar]
- Adult xanthogranuloma, reticulohistiocytosis, and rosai-dorfman disease. Dermatol Clin. 2015;33:465-72.
- [CrossRef] [PubMed] [Google Scholar]
- Solitary (juvenile) xanthogranuloma: A comprehensive immunohistochemical study emphasizing recently developed markers of histiocytic lineage. Hum Pathol. 2015;46:1390-7.
- [CrossRef] [PubMed] [Google Scholar]