Dermatology: Practical and Conceptual 162 Letter | Dermatol Pract Concept 2019;9(2):18 Dermatology Practical & Conceptual Introduction We report the case of a 34-year-old white man with an 8-month history of erythematoviolaceous papulonodules distributed from the left hand to the arm in a sporotri- choid pattern. Case Presentation A papulonodule was initially noted on the tip of the patient’s fourth left finger. More lesions progressed over the next months along his left arm, with associated tenosynovitis of the same finger. Physical examination revealed several nonconfluent, mildly scaling papulonodules on the dorsal aspect of the left hand, forearm, and arm, with a discrete nonpurulent discharge (Figure 1A). Dermoscopy revealed orange structureless areas associated with white scaling, erosions, serohematic crusts, and dotted/glomerular ves- sels (Figure 1B). The remaining physical examination was unremarkable. The patient worked as a waiter and had some fish tanks and a dog with leishmaniasis. A biopsy specimen disclosed mild acanthosis, orthokeratosis, and occasional epidermal erosions (Figure 2A). A diffuse, noncaseating, granulomatous inflammatory infiltrate, composed of lymphocytes, histio- cytes, and multinucleated giant cells, was present in the papil- lary and reticular dermis (Figure 2B). Gram, Ziehl-Neelsen, and PAS stains failed to detect microorganisms. Polymerase chain reactions for both Leishmania spp and Mycobacterium spp were negative. Mycobacterial cultures from a skin biopsy isolated several strains of Mycobacterium marinum. Our patient started treatment with doxycycline 100 mg once daily for 4 weeks plus clarithromycin 500 mg twice daily for 12 weeks. The lesions disappeared, leaving a mild residual hyperpigmentation. Discussion In dermoscopy, orange color is highly suggestive of dermal granulomas, although it has also been described in non- Red and Orange Colors as Dermoscopic Clues for Fish-Tank Granuloma Alejandro Lobato-Berezo1,2, Gemma Martín-Ezquerra1, Ainhoa Vidal-Navarro1, Ramón M. Pujol1 1 Department of Dermatology, Hospital del Mar-Parc de Salut Mar, Barcelona, Spain 2 Department of Dermatology, Hospital Universitari General de Catalunya, Sant Cugat del Vàlles, Barcelona, Spain Key words: orange, red, nodule, arm, fish-tank granuloma Citation: Lobato-Berezo A, Martín-Ezquerra G, Vidal-Navarro A, Pujol RM. Red and orange colors as dermoscopic clues for fish-tank granuloma. Dermatol Pract Concept. 2019;9(2):162-164. DOI: https://doi.org/10.5826/dpc.0902a18 Accepted: November 19, 2018; Published: April 30, 2019 Copyright: ©2019 Lobato-Berezo et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: None. Competing interests: The authors have no conflicts of interest to disclose. Authorship: All authors have contributed significantly to this publication. Corresponding author: Alejandro Lobato-Berezo, MD, Department of Dermatology, Hospital del Mar, Barcelona, Passeig Marítim, 25-29, 08003 Barcelona, Spain. E-mail: allobe@hotmail.es Letter | Dermatol Pract Concept 2019;9(2):18 163 within the dermis. Dotted and glomerular vessels are second- ary to the increased inflammatory granulomatous infiltrate. On the other hand, histological and even molecular diagnosis of fish-tank granuloma can be challenging. Ziehl- Neelsen staining is able to detect acid-fast bacilli in a low number of cases, between 13% and 50%, depending both on the stage and the presence of tuberculoid granulomas. Culture in Löwenstein-Jensen agar can detect Mycobacterium marinum in 93.3% of the cases and is still considered one of the most specific diagnostic tools [3-5]. Conclusions We present the first description of fish-tank granuloma der- moscopy. We would like to highlight the association of orange structureless areas with dotted/glomerular vessels in the der- moscopy as an additional clue to the clinical lesions and the unilateral location to distinguish it from other granulomatous granulomatous diseases [1]. Yellowish to orange color has been the main clue for the description of different patterns in granulomatous diseases. In addition, other dermoscopic fea- tures could help in the diagnosis, for example, long and very branched telangiectasias in necrobiosis lipoidica, short telan- giectasias and white lines and dots between the translucent orange globules in cutaneous sarcoidosis, unfocused vessels in granuloma annulare, pinkish homogeneous background with no or dull orangish areas in rheumatoid nodules, reddish or purple vascular polygons in granulomatous rosacea, yellow tear drops or white starburst pattern in cutaneous leish- maniasis, follicular openings filled with whitish or yellowish keratotic plugs in acne agminata, white areas with areas of alopecia in borderline tuberculoid leprosy, well-focused linear-branching vessels in lupus vulgaris, or granuloma foreign body reaction. These areas may show focal or diffuse distribution [2]. However, lack of this color does not exclude the diagnosis of cutaneous granulomatous disease, mainly at early stages of the disease or when deep granulomas are present in the reticular dermis. In this case, white scales could correspond to epidermal orthokeratosis and orange structureless areas to granulomas Figure 1. (A) Crusted nodule on the left fore- arm. (B) Small orange structureless areas as- sociated with white scaling, erosions, sero- hematic crusts, and dot- ted/glomerular vessels. [Copyright: ©2019 Lo- bato-Berezo et al.] A B Figure 2. (A) Mild acanthosis, orthokeratosis, and occasional epi- dermal erosions (H&E, ×10). (B) Diffuse, noncaseating, granuloma- tous inflammatory infiltrate, composed of lymphocytes, histiocytes, and multinucleated giant cells (H&E, ×40). H&E = hematoxylin and eosin. [Copyright: ©2019 Lobato-Berezo et al.] A B 164 Letter | Dermatol Pract Concept 2019;9(2):18 3. Belz D, Tantcheva-Poor I, Rasokat H, Fabri M, Schlaak M. My- cobacterium marinum infection initially diagnosed as metastatic Crohn’s disease. J Eur Acad Dermatol Venereol. 2016;30(3):514- 515. 4. Bonamonte D, De Vito D, Vestita M, et al. Aquarium-borne Myco- bacterium marinum skin infection: report of 15 cases and review of the literature. Eur J Dermatol. 2013;23(4):510-516. 5. Collina G, Morandi L, Lanzoni A, Reggiani M. Atypical cutane- ous mycobacteriosis diagnosed by polymerase chain reaction. Br J Dermatol. 2002;147(4):781-784. diseases. These dermoscopic findings have been found in a single case and need to be validated in future case series. References 1. Bañuls J, Arribas P, Berbegal L, DeLeón FJ, Francés L, Zaballos P. Yellow and orange in cutaneous lesions: clinical and dermoscopic data. J Eur Acad Dermatol Venereol. 2015;29(12):2317-2325. 2. Errichetti E, Stinco G. Dermatoscopy of granulomatous disorders. Dermatol Clin. 2018;36(4):369-375.