What are the signs and symptoms of Buschke Ollendorff syndrome? Buschke Ollendorff syndrome (BOS) is an association of connective tissue nevi and osteopoikilosis (small, round areas of increased bone density). The nevi are typically present on the trunk, in the sacrolumbar region (lower back and sacrum), and on the extremities (arms and legs). Occasionally, they may be on the head. The nevi are usually nontender and firm, and are typically first noticeable as slightly elevated and flattened yellowish bumps, grouped together and forming plaques that may be several centimeters in diameter. The plaques are typically of irregular shape. They are usually numerous, painless, and develop over several years. The osteopoikilosis typically occurs in the long bones, wrist, foot, ankle, pelvis, and scapula. They are harmless and usually found by chance when radiographs are taken for other purposes, although pain and limited joint mobility have been reported in some individuals. In some individuals, only skin or bone manifestations may be present. Other signs and symptoms of BOS may include nasolacrimal duct obstruction, amblyopia ("lazy eye"), strabismus, benign lymphoid hyperplasia, hypopigmentation (abnormally light skin), and short stature. Congenital spinal stenosis (narrowing of the spine), disc herniation, clubfoot deformity, and nerve root compression may be present. Otosclerosis (abnormal growth of bone in the middle ear) with or without hearing loss may occur, but is rare. The Human Phenotype Ontology provides the following list of signs and symptoms for Buschke Ollendorff syndrome. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Abnormal localization of kidney 90% Abnormality of epiphysis morphology 90% Abnormality of the aorta 90% Abnormality of the metaphyses 90% Abnormality of the teeth 90% Abnormality of the voice 90% Bone pain 90% Generalized hypopigmentation 90% Hearing impairment 90% Hyperostosis 90% Increased bone mineral density 90% Microcephaly 90% Sarcoma 90% Short stature 90% Sinusitis 90% Skeletal dysplasia 90% Visual impairment 90% Mediastinal lymphadenopathy 50% Strabismus 50% Abnormal diaphysis morphology 7.5% Arthralgia 7.5% Arthritis 7.5% Atypical scarring of skin 7.5% Flexion contracture 7.5% Melanocytic nevus 7.5% Myalgia 7.5% Non-midline cleft lip 7.5% Palmoplantar keratoderma 7.5% Recurrent fractures 7.5% Type I diabetes mellitus 7.5% Autosomal dominant inheritance - Hoarse voice - Joint stiffness - Nevus - Osteopoikilosis - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.