Granuloma annulare detected by positron emission tomography with computed tomography in a diffuse large B cell lymphoma

ARTICLE

Auteur(s) : Masahisa Shindo, Yuichi Yoshida, Osamu Yamamoto

Division of Dermatology, Department of Medicine of Sensory and Motor Organs, Faculty of Medicine, Tottori University, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan

We describe a case of granuloma annulare identified by positron emission tomography with computed tomography (PET-CT) in a patient with lymphoma. A 67-year-old Japanese man had been followed for 2 years in our hospital, due to diffuse large B cell lymphoma, Stage IVB. He had received peripheral stem cell transplantation after systemic combination chemotherapy. Whole-body PET-CT was performed for evaluation of recurrence. Images showed 18 F-fluorodeoxyglucose (FDG) true positive accumulation only in his left abdomen area (figure 1A). Lymphoma invasion was suspected, and he was referred to our department. Physical examination showed two light red-brown nodules of 7 mm and 8 mm in diameter on the left abdomen, which were elastic hard in consistency (figure 1B). Microscopic examination showed the presence of histiocytes, lymphocytes, and Langhans-type multinucleated giant cells surrounding degenerative collagen bundles (figure 1C). However, atypical cells, including lymphoma cells, were not seen. A diagnosis of granuloma annulare was made. The nodules disappeared within three months after skin biopsy. There has been no recurrence of the lymphoma. Granuloma annulare is characterized by focal degeneration of dermal collagen bundles surrounded by palisading granuloma. Our case showed typical histopathological features.

PET-CT with FDG has been widely used for the diagnosis and monitoring of malignancies. However, FDG is also known to accumulate in inflammatory and infectious lesions, and, rarely, in benign skin tumors [1, 2]. In the present case, PET-CT for evaluation of possible recurrence of lymphoma showed uptake of FDG in granuloma annulare lesions instead of lymphoma. Increased FDG uptake was ultimately attributed to inflammatory cells in granuloma annulare.

Granulomatous infiltrations, including sarcoidosis [3], annular elastolytic giant cell granuloma [4] and granuloma annulare [5], have been reported in association with malignant blood diseases. Relatively rare cases of granuloma annulare have been reported in patients with B-cell non-Hodgkin’s lymphoma, such as our case [3].

Recently, Dadban et al. reported the first case of widespread granuloma annulare, detected by PET-CT, 2 years before the diagnosis of Hodgkin’s disease [6]. (The authors, however, did not show PET-CT images.) Differential diagnosis between lymphoma and granulomatous diseases is not possible only by PET-CT images. Dermatologists should pay attention to the possibility of false positive skin diseases on PET-CT in the follow-up of patients with malignant tumors, such as malignant lymphoma, and make the final diagnosis based on results of histopathological examinations.

Acknowledgements

References

2 Battistella M, Trabelsi S, Terrier-Lacombe MJ, et al. Hypermetabolic dermatofibroma on Positron Emission Tomography/Computed tomography with 18F-FluoroDeoxyGlucose: a misleading false positive in the follow-up of a metastatic melanoma. Eur J Dermatol 2008; 18: 461-2.

3 Barksdale SK, Perniciaro C, Halling KC, Strickler JG. Granuloma annulare in patients with malignant lymphoma, Clinicopathologic study of thirteen new cases. J Am Acad Dermatol 1994; 31: 42-8.

4 Kuramoto Y, Watanabe M, Tagami H. Adult T cell leukemia accompanied by anular elastolytic giant cell granuloma. Acta Derm Venereol (Stockh) 1990; 70: 164-7.

5 Miyamoto T, Mihara M. Subcutaneous Granuloma Annulare with Hodgkin’s Disease. J Dermatol 1996; 23: 405-7.

6 Dadban A, Slama B, Azzedine A, Lepeu G. Widespread granuloma annulare and Hodgkin’s disease. Clin Exp Dermatol 2008; May 6. [Epub ahead of print] PMID: 18462441.