Histopathologic Aspects of Malignancy-Associated Granuloma Annulare: A Single Institution Experience.

Granuloma annulare (GA) is a benign, self-limiting granulomatous inflammatory disease that exhibits different histologic patterns. Infrequently, granuloma annulare can be associated with malignancy, the so-called malignancy-associated granuloma annulare (MGA). In this study, we aimed to compare the clinical and histopathological differences between GA and MGA. We retrospectively reviewed patient charts and identified 35 patients diagnosed with GA and concurrent hematological or solid organ malignancies as a case group. Additionally, we identified 33 patients without any known solid organ or hematological malignancy as a control group. MGA is commonly seen in the seventh decade of life, while GA affects the younger population. MGA is most commonly presented in the extremities of the body. The most common malignancy associated with MGA was chronic lymphocytic leukemia. Prostate cancer was the most common type of solid organ malignancy that was associated with MGA. The most common histopathological pattern seen in MGA was interstitial, comprising half of the cases. Multinucleated giant cells were present in half of the MGA cases and in most of the control group. In the literature, there are no established features that distinguish MGA from GA. Although MGA and GA have overlapping features, in our series, we found that the interstitial pattern was more common in MGA, while the necrobiotic pattern was more common in GA.

Subepidermal Calcified Nodule in a Child With Neurofibromatosis Type 1.

Calcinosis cutis (CC) is characterized by calcium deposition in the subcutaneous tissues. Subepidermal calcified nodule (SCN) is a variant of idiopathic calcinosis most commonly seen in the head and neck region of children and adolescents as a single, small, painless, yellow-white papule. A 13-year-old boy with a medical history of neurofibromatosis type 1 (NF1) presented with a firm 0.3 cm white papule in the lower eyelid. He also had neurofibromas of the left forearm and spinal cord, and a malignant peripheral nerve sheath tumor of the right forearm. The eyelid lesion showed hyperkeratotic epidermis, papillomatosis, and elongated rete ridges, with a radial arrangement at the periphery of the well-circumscribed lesion comprising many dystrophic calcifications, histiocytes, and foreign body giant cell reactions. To our knowledge, this is the first case of SCN reported in the context of NF1 or any other systemic disease in the English literature. Although a coincidence is likely, rare observations of the parathyroid gland and calcium metabolism disorders in association with NF1 may provide an explanation that requires further investigation.

Granuloma Annulare - A Manifestation of Primary Cutaneous Mucinous Carcinoma?

The objective of this report is to present a rare case of primary cutaneous mucinous carcinoma (PCMC) manifesting with granuloma annulare (GA), and to discuss the association as a paraneoplastic phenomenon. A 65-year-old female presented with a painless, slow-growing, cystic nodule less than 1 cm over the left lateral canthus. The clinical presentation was highly suspicious of sebaceous cyst. The histopathologic examination revealed variable sizes of neoplastic cell clusters in a pool of abundant mucin. A focus of palisading lympho-histiocytic infiltrate surrounding a necrobiosis suggestive of granuloma annulare adjacent to the tumor is identified. Series of extensive investigations performed did not reveal any primary origin. GA can rarely be associated with various malignant conditions. Its association and prognostic importance to these conditions are unclear. The presence with certain malignancies and the resolution of GA with the treatment of underlying malignancy are an indicator that this condition can very well be a paraneoplastic phenomenon.