Sarcoidosis: Although the lung biopsy showed no granulomas, sarcoidosis can present with skin granulomas in tattooed areas (a condition known as sarcoidosis in tattoos) and mildly enlarged lymph nodes. The absence of granulomas in the lung biopsy does not rule out sarcoidosis, as the disease can be patchy.

Foreign Body Reaction to Tattoo Ink: This is a common cause of skin granulomas in tattooed areas. The reaction can occur years after the tattoo was placed and could potentially cause a mild systemic reaction, including enlarged lymph nodes.
Granulomatous Reaction to Tattoo Pigments: Similar to a foreign body reaction, certain tattoo pigments can cause a granulomatous reaction, leading to skin granulomas in the tattooed areas.

Lymphoma: Although less likely, lymphoma (such as Hodgkin lymphoma) can cause granulomatous reactions and enlarged lymph nodes. It's crucial to consider this diagnosis due to its significant implications for treatment and prognosis.
Tuberculosis (TB): TB can cause granulomas and enlarged lymph nodes. Although the lung biopsy was negative, TB can affect any part of the body, and a high index of suspicion is necessary, especially if the patient has risk factors for TB.

Berylliosis (Chronic Beryllium Disease): This is a rare condition caused by exposure to beryllium, leading to granulomatous disease that can affect the lungs and skin. It's an occupational disease and would be considered if the patient has a relevant exposure history.
Blau Syndrome: A rare genetic disorder characterized by granulomatous dermatitis, symmetric arthritis, and recurrent uveitis. It could potentially cause skin granulomas in unusual locations, including tattoos, though it's extremely rare.