Clinical Challenge: Brown Macules on the Lips, Fingers

Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant disorder characterized by hamartomatous polyps in the gastrointestinal tract and pigmented mucocutaneous macules (lentigines) on the lips and buccal mucosa. More than 80% of patients with PJS are diagnosed after presenting with...

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Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant disorder characterized by hamartomatous polyps in the gastrointestinal tract and pigmented mucocutaneous macules (lentigines) on the lips and buccal mucosa. More than 80% of patients with PJS are diagnosed after presenting with gastrointestinal complaints. The remaining cases are detected based on the characteristic pattern of melanin pigmentation.

The appearance of dark brown to blue-gray macules arises in infancy and early childhood, and is often the earliest manifestation of PJS. These small, flat hyperpigmented spots (1-5mm) tend to cluster and localize to the vermilion border of the lips and buccal mucosa. Pigmentation may also be found on the nose, fingers, palms, soles and around the eyes and perianal region.

Cutaneous lesions on the lips often grow in size and number until puberty, after which they may begin to fade. Mucosal pigmentation inside the oral cavity is a pathognomonic sign of PJS and does not tend to regress over time. Malignant transformation of the macules is extremely rare.

Gastrointestinal polyps found in PJS develop in the first decade of life and typically produce symptoms in adolescence and early adulthood. Over half of patients with PJS experience gastrointestinal complications such as abdominal pain, rectal bleeding, and anemia before the age 20 years. Although polyps most frequently grow in the small intestine -specifically the jejunum- they may also be detected in the stomach and colon.

Intussusception in the small intestine is a major complication, especially in pediatric patients. Most patients experience a small bowel obstruction, either due to intussusception or occlusion of the intestinal lumen by a polyp, at least once during their lifetime.

More than 90% of individuals with a clinical diagnosis of PJS have a germline mutation in the tumor suppressor STK11 gene, which encodes a serine threonine kinase. There is molecular genetic testing available for this mutation. Those with PJS have an increased lifetime risk of developing intestinal malignancies such as colorectal cancer, in addition to carcinomas of the stomach, pancreas, lungs, breasts, and ovaries.

Due to the significant risk of malignancy, patients require regular cancer surveillance.

Other Answer Choices

Laugier-Hunziker syndrome (LHS) is a rare benign condition characterized by macular hyperpigmentation of the oral mucosa and lips. LHS is frequently associated with longitudinal melanonychia and genital melanosis. The pathogenesis is unknown, although there are no malignant potential or underlying systemic abnormalities associated with LHS.

Patients present with multiple flat, smooth, gray to brown-black lenticular macules (2-5mm) on the oral mucosa and lips. Hyperpigmented lesions may also appear on the neck, chest, abdomen, vulva, penis, perineum, and perianal skin. Although LHS shares some clinical features with PJS, LHS lacks hamartomatous polyposis and familial history. Unlike in PJS, the pigmented lesions of LHS are progressively acquired after puberty.

Cronkhite-Canada syndrome (CCS) is a rare noninherited, sporadically occurring disorder characterized by diffuse polyposis of the gastrointestinal tract, particularly in the stomach and colon. Clinical presentation includes chronic diarrhea and protein-losing enteropathy, as well as dermatologic findings of alopecia, onychodystrophy, and cutaneous hyperpigmentation.

The etiology of CCS is unknown, but it is thought to be autoimmune-mediated since individuals with CCS tend to have elevated levels of antinuclear antibody and IgG4. CCS can be found worldwide, but three-fourths of reported cases involve patients of Japanese descent. Potential fatal complications include malnutrition, gastrointestinal bleeding, congestive heart failure, and sepsis.

Julie Ngyuen is a medical student at Baylor College of Medicine.

Adam Rees, MD, a graduate of the David Geffen School of Medicine at UCLA, practices dermatology in Los Angeles.

References

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