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CORRESPONDENCE |
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| Year : 2022 | Volume
: 67
| Issue : 4 | Page : 448-450 |
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| Basal cell carcinoma or trichoblastoma? Two cases of nasal nodules difficult to distinguish |
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Zhiqiang Cao, Yuanyuan Liu, Guo Wei, Zhaoyang Liu, Chunhong Zhang
From the Department of Dermato-venereology, The Second Hospital of Shandong University, Jinan, China
| Date of Web Publication | 2-Nov-2022 |
Correspondence Address:
Zhiqiang Cao
From the Department of Dermato-venereology, The Second Hospital of Shandong University, Jinan
China
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/ijd.ijd_197_22
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How to cite this article:
Cao Z, Liu Y, Wei G, Liu Z, Zhang C. Basal cell carcinoma or trichoblastoma? Two cases of nasal nodules difficult to distinguish. Indian J Dermatol 2022;67:448-50 |
How to cite this URL:
Cao Z, Liu Y, Wei G, Liu Z, Zhang C. Basal cell carcinoma or trichoblastoma? Two cases of nasal nodules difficult to distinguish. Indian J Dermatol [serial online] 2022 [cited 2023 Apr 1];67:448-50. Available from: https://www.e-ijd.org/text.asp?2022/67/4/448/360317 |
Sir,
Trichoblastoma (TB) is a rare, slow-growing, benign skin tumour that can be primary or evolve from a sebaceous nevus. It can appear on any surface of hair follicles, oftentimes located on the scalp and face. TB usually presents clinically as an asymptomatic, solitary, well-circumscribed, skin-colored papule or nodule without ulceration. It generally exhibits a good prognosis and a low incidence of recurrence, progression, or association with malignancy. Its main differential diagnosis is nodular basal cell carcinoma (BCC) as it shows similar clinical and dermatoscopic features. BCC, which is the most common cutaneous malignancy worldwide, is an aggressive but rarely metastasizing cancer, often occurring on the face. It has diverse clinical presentations, the most common being a pearly pink nodule exposed to sunlight with capillary dilation. In this report, we describe two cases, TB and BCC, both presenting with similar skin-colored nodules located on the nose with arborising vessels as predominant dermatoscopy manifestation.
Case 1 was a 58-year-old male with a nodule located on his nose for 10 years. The dermatological examination revealed a soy-sized skin-coloured nodule, with clear boundaries, a smooth surface, and an intact skin, but no tenderness [Figure 1]a. Dermatoscopy revealed a pale red background with visible white shiny areas and short, thin, poorly branched vessels [Figure 1]b and [Figure 1]c. We initially considered this to be a nodular BCC. However, following a histopathological examination, the final diagnosis was TB [Figure 1]d. | Figure 1: Case 1. The clinical, dermatoscopic, and histopathological manifestations of trichoblastoma. (a) A nasal skin-coloured nodule. (b and c) Dermatoscopy findings: pale red background with visible white shiny areas and short, thin, poorly branched vessels. (d) The tumour cells showed multi-nodular distribution, which proliferated in the dermis arranged in nests and cords. The peripheral cells were arranged in a palisading pattern, and the contraction gap was not obvious. The original hair papilla-like structure was seen locally with pigmentation (HE-stained)
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Case 2 was a 50-year-old female with a skin-coloured nodular lesion of unknown onset on the tip of her nose for 3 years. The nodule had been gradually increasing in size, without conscious symptoms. The dermatological assessment indicated an isolated, granuloma-like nodule on the tip of her nose, with a smooth surface and no ulceration or tenderness [Figure 2]a. Dermatoscopy revealed a red background with larger and more branched arborising vessels without pigmentation, along with a maple leaf-like structure [Figure 2]b and [Figure 2]c. The results of the histopathological assay were suggestive of BCC, but TB could not be excluded [Figure 2]d. Immunohistochemistry results revealed that CK (epithelial) and BER-EP4 were positive, CK20 (epithelial) and CEA (tumour cells) were negative, and CK10 (stroma) was weakly positive. Based on these findings, a diagnosis of BCC was proposed. | Figure 2: Case 2. The clinical, dermatoscopic, and histopathological manifestations of basal cell carcinoma. (a) A nasal nodule with capillary dilation. (b and c) Dermatoscopic images: multiple larger and more branched ''tree-like'' arborising telangiectasias in a red background and a maple leaf-like structure were observed. (d) In the sub-epithelium, the tumour cells were arranged in a nested, sieve-like pattern; at the periphery, they were proliferating in a palisading pattern and artificial contraction gaps were seen, but there was no clear primitive hair papilla-like structure (HE-stained)
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Dermatoscopy is a non-invasive technique that has greatly improved the diagnostic accuracy of skin tumours, such as those of BCC; however, benign adnexal tumours may resemble BCC. Arborising vessels are common in many skin tumours, such as sebaceous gland hyperplasia, melanocytic nevus, BCC, and seborrheic keratosis.[1] Research showed that arborising vessels are one of the important diagnostic features in the dermatoscopy of BCC, which are larger and more diffusely branched in nodular BCC but have fine, short, and scarce branches in TB.[2] Short and sparsely branched capillary dilations have been observed in other skin tumours, such as trichoepithelioma, fibroproliferative trichoepithelioma, and Pinkus fibroepithelioma. Although, this vascular pattern has been observed in distinct tumours which are similar to TB, it may serve as a symptom for the differential diagnosis of nodular BCC.[3]
In TB, arborising vessels, coronary vessels, a pearly white background, and cornual cysts are all structures that have been previously described in BCC.[3] Some key discriminatory histological attributes of TB include a well-circumscribed, symmetrical, and basaloid tumour with no epidermal connections along with an absence of inflammatory infiltrate and absent or focal necrosis, usually located in the mid to lower dermis. In contrast, BCC originates from the epidermis, with lymphocytic infiltrate and variable necrosis.[4],[5] TB also differs from BCC with its variable stromal condensation and pilar differentiation, whereas BCC is characterised by basaloid nodules, with prominent peripheral palisading and clefting between the neoplasm and surrounding stroma.[4] It is sometimes necessary to use immunohistochemistry to discriminate between a BCC versus TB lesion, with CD 10, CD 34, and PHLDA1 all staining positive in TB but negative in BCC.
Our cases suggest that dermatoscopic presentation of fine, poorly branched arborising vessels supports the diagnosis of TB and can be used in the differential diagnosis of nodular BCC, but there remain limitations in the diagnosis with this technique.[5] These two conditions have different prognoses and require different treatments; therefore, they must be distinguished. Histopathology and immunohistochemistry assays remain the gold standard for diagnosing and differentiating TB from BCC.
Acknowledgements
All the authors thank the provider of dermatoscopic pictures of BCC, Lu Cui.
Informed consent
Informed consent was obtained from the patients for the publication of this report.
Financial support and sponsorship
This work was supported by the National Natural Science Foundation of China under Grant 81973856.
Conflicts of interest
There are no conflicts of interest.
 References | |  |
| 1. | Argenziano G, Zalaudek I, Corona R, Sera F, Cicale L, Petrillo G, et al. Vascular structures in skin tumors: A dermoscopy study. Arch Dermatol 2004;140:1485-9.  |
| 2. | Pitarch G, Botella-Estrada R. Dermoscopic findings in trichoblastoma. Actas Dermosifiliogr 2015;106:e45-8. |
| 3. | Cabrera R, Matus P, Coulon G, Castro A, Reculé F. Skin collision tumour and dermoscopic diagnosis of melanoma in situ and dilated pore of Winer. Australas J Dermatol 2022;63:98-101. |
| 4. | Patel P, Nawrocki S, Hinther K, Khachemoune A. Trichoblastomas mimicking basal cell carcinoma: The importance of identification and differentiation. Cureus 2020;12:e8272. |
| 5. | Ghigliotti G, De Col E, Parodi A, Bombonato C, Argenziano G. Trichoblastoma: Is a clinical or dermoscopic diagnosis possible? J Eur Acad Dermatol Venereol 2016;30:1978-80. |
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